High protein nuggets and applications in food products

ABSTRACT

The present invention relates to food materials containing a high concentration of protein and processes for their manufacture. More particularly, the present invention relates to protein extrudates containing high concentrations of soy protein, dairy protein, and mixtures thereof and low concentrations of carbohydrates, processes for manufacturing such protein extrudates, and the use of such protein extrudates as functional food ingredients.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part patent application of U.S.patent application Ser. No. 10/817,741, entitled HIGH SOY PROTEINNUGGETS AND APPLICATIONS IN FOOD PRODUCTS, filed on Apr. 2, 2004.

FIELD OF THE INVENTION

The present invention relates to food materials containing a highconcentration of vegetable protein dairy protein, and mixtures thereofand processes for their manufacture. More particularly, the presentinvention relates to protein extrudates containing high concentrationsof vegetable protein, dairy protein and mixtures thereof and lowconcentrations of carbohydrates, processes for manufacturing suchprotein extrudates, and the use of such protein extrudates as functionalfood ingredients.

BACKGROUND OF THE INVENTION

Texturized protein products are known in the art and are typicallyprepared by heating a mixture of protein material along with water undermechanical pressure in a cooker extruder and extruding the mixturethrough a die. Upon extrusion, the extrudate generally expands to form afibrous cellular structure as it enters a medium of reduced pressure(usually atmospheric). Expansion of the extrudate results from inclusionof soluble carbohydrates which reduce the gel strength of the mixture.The extrudates are then used to form other products such as vegetablemeat analogs. Extrusion methods for forming textured protein meatanalogs are well known and disclosed, for example, in U.S. Pat. No.4,099,455.

Extrusion cooking devices have long been used in the manufacture of awide variety of edible and other products such as human and animalfeeds. Generally speaking, these types of extruders include an elongatedbarrel together with one or more internal, helically flighted, axiallyrotatable extrusion screws therein. The outlet of the extruder barrel isequipped with an apertured extrusion die. In use, a material to beprocessed is passed into and through the extruder barrel and issubjected to increasing levels of temperature, pressure and shear. Asthe material emerges from the extruder die, it is fully cooked andshaped and may typically be subdivided using a rotating knife assembly.Conventional extruders of this type are described, for example, in U.S.Pat. Nos. 4,763,569, 4,118,164 and 3,117,006, which are incorporatedherein by reference.

Attempts to develop processes for producing suitable meat substitutesfrom vegetable protein sources include extrusion cooking defatted soyflour or other vegetable proteins in order to texturize and orient thevegetable protein and produce meat extenders in the form of texturizedprotein products for use with hamburger or similar products. Exemplaryprocesses of this type are taught in U.S. Pat. Nos. 3,047,395;3,142,571;

3,488,770 and 3,870,805. Although these extrusion processes have metwith a certain degree of acceptance in the art, the meat substituteproducts heretofore produced have possessed several characteristicswhich have seriously limited their use, particularly as full substitutesfor meat. One of the most persistent objections to those prior productsstems from the expanded, cellular, spongy nature thereof. In particular,most of these meat extenders are produced under high pressure andtemperature conditions in the extrusion cooker which results in atwisted, randomly oriented meat extender. After rehydration, theseextenders are characterized by a chewy structure of twisted layerslacking the appearance, mouth feel or range of utility of meat. This hasfor the most part limited the use of these products to the role of meatextenders in ground hamburger type meats and the like. Moreover, if toomuch of the prior vegetable protein product is employed in suchhamburger-type meats, the extended meat becomes unacceptably spongy andexhibits a random, unappealing appearance and mouth feel.

Alternatively, the texturized protein product may be cut into smallerextrudates such as “nuggets” or powders for use as food ingredients oras functional food products.

Regardless of its form, texturized protein products must have anacceptable density, texture, and mouth feel for use as a foodingredient. Thus, conventional texturized protein products typicallyhave a protein content of from about 40% to about 60% by weight on amoisture-free basis. Increasing the protein content of the texturizedproduct has not been feasible because a significant fraction ofcarbohydrate has been deemed necessary to provide the protein extrudatewith an acceptable texture and density. But in certain instances highcarbohydrate functional food ingredients are undesirable to consumerswishing to reduce carbohydrate intake. Thus, a need exists for a highprotein, low carbohydrate texturized protein product having anacceptable density, texture and mouth feel for use as a functional foodingredient.

SUMMARY OF THE INVENTION

The present invention discloses novel protein extrudates having a highconcentration of protein and a low concentration of carbohydrates. Theextrudates have a lower density than conventional protein extrudatescontaining high levels of protein. The protein extrudates typically havea color L value of greater than 50. The extrudates can be used as aningredient or a source of protein in food products. The novel proteinextrudates can be obtained using vegetable protein products and dairyprotein products either alone or in various combinations depending onthe desired attributes of the finished product.

Briefly, therefore, in one embodiment, the present invention is directedto a protein extrudate comprising at least about 70% by weight vegetableprotein on a moisture-free basis and having a density of from about 0.10g/cm³ to about 0.40 g/cm³.

In one embodiment, the present invention is directed to a proteinextrudate comprising at least about 70% by weight dairy protein on amoisture-free basis and having a density of from about 0.10 g/cm³ toabout 0.40 g/cm³.

In one embodiment, the present invention is directed to a proteinextrudate comprising at least about 70% by weight vegetable protein,dairy protein and mixtures therof on a moisture-free basis and having adensity of from about 0.10 g/cm³ to about 0.40 g/cm³.

In another embodiment, the present invention is directed to a proteinextrudate comprising unhydrolyzed vegetable protein and at least about 2parts by weight hydrolyzed protein per part by weight unhydrolyzedprotein.

In another embodiment, the present invention is directed to a proteinextrudate comprising unhydrolyzed dairy protein and at least about 2parts by weight hydrolyzed protein per part by weight unhydrolyzedprotein.

In another embodiment, the present invention is directed to a proteinextrudate comprising unhydrolyzed vegetable protein, dairy protein andmixtures thereof and at least about 2 parts by weight hydrolyzed proteinper part by weight unhydrolyzed protein.

In a further embodiment, the present invention is directed to a proteinextrudate comprising at least about 70% by weight unhydrolyzed vegetableprotein on a moisture-free basis and having a density from about 0.10.g/cm³ to about 0.40 g/cm³.

In a further embodiment, the present invention is directed to a proteinextrudate comprising at least about 70% by weight unhydrolyzed dairyprotein on a moisture-free basis and having a density from about 0.10.g/cm³ to about 0.40 g/cm³.

In a further embodiment, the present invention is directed to a proteinextrudate comprising at least about 70% by weight unhydrolyzed vegetableprotein, dairy protein and mixtures thereof on a moisture-free basis andhaving a density from about 0.10. g/cm³ to about 0.40 g/cm³.

In another embodiment, the present invention is directed to a functionalfood ingredient comprising from about 40% to about 95% by weight meatmaterial and up to about 4% by weight of a protein product on a totalweight basis, the protein product comprising at least about 70% byweight protein on a moisture-free basis and having a density of fromabout 0.10 g/cm³ to about 0.40 g/cm³. The protein can be vegetableprotein, dairy protein, and mixtures thereof The vegetable proteins arederived from seed crops selected from the groups of cereal grains,legumes and mixtures thereof. The dairy proteins include caseinates,whey and mixtures thereof.

In another embodiment, the present invention is directed to a lowdensity snack food product including a majority solids component and awater component with the majority solids component including at leastprotein. The food product comprises protein in the range of betweenabout 25% and about 95% by weight of majority solids component andwater, the protein can be vegetable protein, dairy protein and mixturesthereof; water in the range of between about 1% and about 7% by weightof solids and water; and the product is characterized by having a crisptexture, a density in the range of between about 0.02 g/cm³ and about0.5 g/cm³ based on the weight of solids component and water. Thevegetable proteins are derived from seed crops selected from the groupsof cereal grains, legumes and mixtures thereof. The dairy proteinsinclude caseinates, whey and mixtures thereof.

In another embodiment, the present invention is directed to a lowdensity, low moisture content proteinaceous food product comprising aprincipal solid component and containing between about 1% and about 7%water. The principal solid component comprises protein in aconcentration between about 25% and about 95% by weight of the sum ofthe water content of the product and the dry basis weight of theprincipal solid component, the product being characterized by a crisptexture and a density in the range between about 0.02 g/cm³ and about0.5 g/cm³ based on the weight of said principal solid component andwater. The proteins can be vegetable proteins, dairy proteins, andmixtures thereof. The vegetable proteins are derived from seed cropsselected from the groups of cereal grains, legumes and mixtures thereof.The dairy proteins include caseinates, whey and mixtures thereof.

In another embodiment, the present invention is directed to a lowdensity, low moisture content proteinaceous food product comprising aproteinaceous solid matrix and containing between about 1% and about 7%water. The matrix comprises protein in a concentration between about 25%and about 95% by weight of the sum of the water content of the productand the dry basis weight of said matrix, the product being characterizedby a crisp texture, a density in the range between about 0.02 g/cm³ andabout 0.5 g/cm³. The proteins can be vegetable proteins, dairy proteins,and mixtures thereof. The vegetable proteins are derived from seed cropsselected from the groups of cereal grains, legumes and mixtures thereofThe dairy proteins include caseinates, whey and mixtures thereof.

In another embodiment, the present invention is directed to a lowdensity, low moisture content proteinaceous food product comprising aproteinaceous solid extrudate and containing between about 1% and about7% water. The extrudate comprises protein in a concentration betweenabout 25% and about 95% by weight of the sum of the water content of theproduct and the dry basis weight of said extrudate, the product beingcharacterized by a crisp texture, a density in the range between about0.02 g/cc and about 0.5 g/cc. The proteins can be vegetable proteins,dairy proteins, and mixtures thereof. The vegetable proteins are derivedfrom seed crops selected from the groups of cereal grains, legumes andmixtures thereof. The dairy proteins include caseinates, whey andmixtures thereof.

In another embodiment, the present invention is directed to a lowdensity, low moisture content proteinaceous food product comprisingbetween about 1% and about 7% water and between about 25% and about 95%by weight of protein, wet basis, the product being characterized by acrisp texture, and a density in the range between about 0.02 g/cm³ andabout 0.5 g/cm³. The proteins can be vegetable proteins, dairy proteins,and mixtures thereof The vegetable proteins are derived from seed cropsselected from the groups of cereal grains, legumes and mixtures thereofThe dairy proteins include caseinates, whey and mixtures thereof.

In a further embodiment, the present invention is directed to a cocoaprotein extrudate comprising at least about 70% by weight protein on amoisture-free basis and having a density of from about 0.10 g/cm³ toabout 0.40 g/Cm³. The protein can be vegetable protein, dairy proteinand mixtures thereof The vegetable proteins are derived from seed cropsselected from the groups of cereal grains, legumes and mixtures thereof.The dairy proteins include caseinates, whey and mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flow sheet of a process useful in preparing theprotein extrudates of the present invention.

FIG. 2 is a photomicrograph of high soy protein textured productsprepared in accordance with the present invention.

FIG. 3 is a photomicrograph of high soy protein textured productsprepared in accordance with the present invention.

FIG. 4 is a photomicrograph of high soy protein textured productsprepared in accordance with the present invention.

FIG. 5 is a photomicrograph of high soy protein textured productsprepared in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, it has been discovered thattextured protein products containing high concentrations of protein andlow concentrations of carbohydrates can be manufactured to have adesired density and an acceptable texture using extrusion technology.Such protein extrudates can be formed as “nuggets” or pellets for use asan ingredient or source of protein in health and nutrition bars, snackbars and ready to eat cereal. Alternatively, the protein extrudates maybe further processed for use as a binder, a stabilizer or a source ofprotein in beverages, health and nutrition bars, dairy, and baked andemulsified/ground meat food systems. In certain embodiments, the proteinextrudates may be ground into fine particles (i.e., powder) to allow forincorporation into soy beverages. Such ground particles typically have aparticle size of from approximately 1 to about 5 μm to allow suspensionin a liquid.

A process of the present invention for preparing protein extrudatesgenerally comprises forming a pre-conditioned feed mixture by contactingthe feed mixture with moisture, introducing the pre-conditioned feedmixture into an extruder barrel, heating the pre-conditioned feedmixture under mechanical pressure to form a molten extrusion mass, andextruding the molten extrusion mass through a die to produce a proteinextrudate.

The protein-containing feed mixture typically comprises at least onesource of protein and has an overall protein concentration of at leastabout 70% protein by weight on a moisture-free basis. Proteins containedin the feed mixture may be obtained from one or more suitable sourcesincluding, for example, dairy protein materials and vegetable proteinmaterials. Dairy protein materials include, for example, casein,caseinate, sweet dairy whey, and acid derived dairy whey. The term wheyis defined as including whey derived from sweet dairy whey or acidderived whey. Vegetable protein materials may be obtained from cerealgrains such as wheat, corn, and barley, and vegetables such as legumes,including soybeans and peas. Preferably, when the feed mixture containsvegetable proteins a soy protein material is the source of the protein,and when the feed mixture contains dairy proteins, calcium caseinate,sodium caseinate, whey and mixtures thereof is the source of theprotein.

Suitable soy protein materials include soy flakes, soy flour, soy grits,soy meal, soy protein concentrates, soy protein isolates, and mixturesthereof. The primary difference between these soy protein materials isthe degree of refinement relative to whole soybeans. Soy flakes aregenerally produced by dehulling, defatting, and grinding the soybean andtypically contain less than about 65 wt.% soy protein on a moisture-freebasis. Soy flakes also contain soluble carbohydrates, insolublecarbohydrates such as soy fiber, and fat inherent in soy. Soy flakes maybe defatted, for example, by extraction with hexane. Soy flours, soygrits, and soy meals are produced from soy flakes by comminuting theflakes in grinding and milling equipment such as a hammer mill or an airjet mill to a desired particle size. The comminuted materials aretypically heat treated with dry heat or steamed with moist heat to“toast” the ground flakes and inactivate anti-nutritional elementspresent in soy such as Bowman-Birk and Kunitz trypsin inhibitors. Heattreating the ground flakes in the presence of significant amounts ofwater is avoided to prevent denaturation of the soy protein in thematerial and to avoid costs involved in the addition and removal ofwater from the soy material. The resulting ground, heat treated materialis a soy flour, soy grit, or a soy meal, depending on the averageparticle size of the material. Soy flour generally has a particle sizeof less than about 150 μm. Soy grits generally have a particle size ofabout 150 to about 1000 μm. Soy meal generally has a particle size ofgreater than about 1000 μm.

Soy protein concentrates typically contain about 65 wt. % to about 85wt. % soy protein, with the major non-protein component being fiber. Soyprotein concentrates are typically formed from defatted soy flakes bywashing the flakes with either an aqueous alcohol solution or an acidicaqueous solution to remove the soluble carbohydrates from the proteinand fiber. On a commercial scale, considerable costs are incurred withthe handling and disposing of the resulting waste stream.

Soy protein isolates, more highly refined soy protein materials, areprocessed to contain at least 90% soy protein and little or no solublecarbohydrates or fiber. Soy protein isolates are typically formed byextracting soy protein and water soluble carbohydrates from defatted soyflakes or soy flour with an alkaline aqueous extractant. The aqueousextract, along with the soluble protein and soluble carbohydrates, isseparated from materials that are insoluble in the extract, mainlyfiber. The extract is typically then treated with an acid to adjust thepH of the extract to the isoelectric point of the protein to precipitatethe protein from the extract. The precipitated protein is separated fromthe extract, which retains the soluble carbohydrates, and is dried afterbeing adjusted to a neutral pH or is dried without any pH adjustment. Ona commercial scale, these steps contribute significant cost to theproduct.

Any dairy protein material can be used to make the protein extrudate.Suitable dairy proteins include caseinates, such as calcium caseinateand sodium caseinate, and whey, including whey protein isolates and wheyprotein concentrates. The dairy proteins can be hydrolyzed, unhydrolyzedand mixtures thereof In preparation of the high protein extrudates, afeed mixture comprising at least about 70 wt. % protein, on amoisture-free basis (i.e., dry basis), is prepared. More preferably, thefeed mixture comprises at least about 80% by weight protein on amoisture-free basis and, still more preferably, the feed mixturecomprises at least about 90% by weight protein on a moisture-free basis.

The overall protein content of the feed mixture may be achieved by acombination (i.e., blend) of suitable sources of protein describedabove.

In certain embodiments, when soy protein is used, it is preferred forsoy protein isolates to constitute one or more of the sources of proteincontained in the feed mixture. This is generally due to the higherdegree of refinement of soy protein isolates as compared to the othersoy protein materials described above and, in particular, due to soyprotein isolates containing the highest protein content and lowestcarbohydrate content of the soy protein materials. For example, apreferred feed mixture formulation may comprise a blend of two or moresoy protein isolates. Other suitable formulations may comprise a soyprotein concentrate in combination with a soy protein isolate.Typically, a protein-containing feed mixture comprising one or more soyprotein isolates contains from about 75% to about 100% by weight soyprotein isolate on a moisture-free basis and, accordingly, from about70% to about 95% by weight protein.

Generally, the bulk density of the source of soy protein, dairy protein,or blend of sources is from about 0.20 g/cm³ to about 0.50 g/cm³ and,more typically, from about 0.24 g/cm³ to about 0.44 g/cm³.

In certain embodiments in which the feed mixture comprises a pluralityof soy protein materials it is desired that at least one of the soyprotein materials exhibits low viscosity and low gelling properties. Theviscosity and/or gelling properties of an isolated soy protein may bemodified by a wide variety of methods known in the art. For example, theviscosity and/or gelling properties of a soy protein isolate may bedecreased by partial hydrolysis which partially denatures the proteinmaterials. Typically, soy protein materials treated in this manner aredescribed in terms of degree of hydrolysis which can be determined basedon molecular weight distributions, sizes of proteins and chain lengths,or breaking down of beta-conglycinin or glycinin storage proteins. Asused herein, the term “percent degree of hydrolysis” of a sample isdefined as the percentage of cleaved peptide bonds out of the totalnumber of peptide bonds in the sample. The proportion of cleaved peptidebonds in a sample can be measured by calculating the amount oftrinitrobenzene sulfonic acid (TNBS) that reacts with primary amines inthe sample under controlled conditions.

Trinitrobenzene sulfonic acid (TNBS) reacts under controlled conditionswith the primary amines of proteins to produce a chromophore whichabsorbs light at 420 nm. The intensity of color produced from theTNBS-amine reaction is proportional to the total number of aminoterminal groups and therefore is an indicator of the degree ofhydrolysis of a sample. In conducting the TNBS assay, 0.2 ml of 0.3 MTNBS solution is reacted with 2 ml of a protein sample prepared byslurrying 0.1 grams of protein material in 100 ml of 0.0245 NaOH. Thereaction is carried out in the presence of a 9.5 pH sodium boratebuffer. The reaction is allowed to proceed for 15 minutes after whichtime the reaction is terminated and the absorbance of the reactionsolution and the protein sample are measured. The absorbance valuesprovide the TNBS value which represents the moles of free amino acidsproduced per 100 kg of protein which is calculated according to thefollowing formula: TNBS value=(As₄₂₀−Ab₄₂₀)×(8.073)×(1/W)×F×100/P. As₄₂₀is the TNBS absorbance of the sample. Ab₄₂₀ is the TNBS absorbance ofthe reaction solution. W is the weight of sample. F is the inverse ofdilution factor of the measured sample to the sample produced by thereaction (i.e., diluting the reaction sample by a factor of 10 beforemeasuring its absorbance provides a dilution factor of 0.1). 8.073 isthe extinction coefficient and dilution factor/unit conversion for theprocedure. P is the protein content of the sample determined using theKjeldahl method described below. Such measurement procedures aredescribed, for example, by Adler-Nissen in J. Agric. Food Chem., Vol.27(6), p. 1256 (1979).

Percent (%) degree of hydrolysis is determined from the TNBS value usingthe following equation: % degree ofhydrolysis=((TNBS_(value)−24)/885)×100. 24 is the correction for lysylamino group of a non-hydrolyzed sample and 885 is the moles of aminoacid per 100 kg of protein.

The Nitrogen-Ammonia-Protein Modified Kjeldahl Method of A.O.C.S.Methods Bc4-91 (1997), Aa 5-91 (1997), and Ba 4d-90(1997) used in thedetermination of the protein content may be performed as follows with asoy material sample. 0.0250-1.750 grams of the soy material are weighedinto a standard Kjeldahl flask. A commercially available catalystmixture of 16.7 grams potassium sulfate, 0.6 grams titanium dioxide,0.01 grams of copper sulfate, and 0.3 grams of pumice is added to theflask, then 30 milliliters of concentrated sulfuric acid is added to theflask. Boiling stones are added to the mixture, and the sample isdigested by heating the sample in a boiling water bath for approximately45 minutes. The flask should be rotated at least 3 times during thedigestion. 300 milliliters of water is added to the sample, and thesample is cooled to room temperature. Standardized 0.5N hydrochloricacid and distilled water are added to a distillate receiving flasksufficient to cover the end of a distillation outlet tube at the bottomof the receiving flask. Sodium hydroxide solution is added to thedigestion flask in an amount sufficient to make the digestion solutionstrongly alkaline. The digestion flask is then immediately connected tothe distillation outlet tube, the contents of the digestion flask arethoroughly mixed by shaking, and heat is applied to the digestion flaskat about a 7.5-min boil rate until at least 150 milliliters ofdistillate is collected. The contents of the receiving flask are thentitrated with 0.25N sodium hydroxide solution using 3 or 4 drops ofmethyl red indicator solution--0.1% in ethyl alcohol. A blankdetermination of all the reagents is conducted simultaneously with thesample and similar in all respects, and correction is made for blankdetermined on the reagents. The moisture content of the ground sample isdetermined according to the procedure described below (A.O.C.S OfficialMethod Ba 2a-38). The nitrogen content of the sample is determinedaccording to the formula: Nitrogen (%)=1400.67×[[(Normality of standardacid)×(Volume of standard acid used for sample (ml))]−[(Volume ofstandard base needed to titrate 1 ml of standard acid minus volume ofstandard base needed to titrate reagent blank carried through method anddistilled into 1 ml standard acid (ml))×(Normality of standardbase)]−[(Volume of standard base used for the sample (ml))×(Normality ofstandard base)]]/(Milligrams of sample). The protein content is 6.25times the nitrogen content of the sample for soy protein and 6.38 timesthe nitrogen content of the sample for dairy protein.

The term “moisture content” as used herein refers to the amount ofmoisture in a material. The moisture content of a soy material and/ordairy material can be determined by A.O.C.S. (American Oil ChemistsSociety) Method Ba 2a-38 (1997), which is incorporated herein byreference in its entirety. According to the method, the moisture contentof the material may be measured by passing a 1000 gram sample of thematerial through a 6×6 riffle divider, available from Seedboro EquipmentCo., Chicago, Ill., and reducing the sample size to 100 grams. The 100gram sample is then immediately placed in an airtight container andweighed. 5 grams of the sample are weighed onto a tared moisture dish(minimum 30 gauge, approximately 50×20 millimeters, with a tight-fittingslip cover—available from Sargent-Welch Co. (Buffalo Grove, Ill.)). Thedish containing the sample is placed in a forced draft oven and dried at130±3° C. for 2 hours. The dish is then removed from the oven, coveredimmediately, and cooled in a dessicator to room temperature. The dish isthen weighed. Moisture content is calculated according to the formula:Moisture content (%)=100×[(loss in mass (grams)/mass of sample (grams)].

Hydrolyzed protein materials used in accordance with the process of thepresent invention typically exhibit TNBS values of less than about 160,more typically less than about 115 and, still more typically, from about30 to about 70.

Hydrolyzed soy protein and/or dairy whey protein sources sufficient foruse as a low viscosity/low gelling material in the process of thepresent invention typically have a degree of hydrolysis of less thanabout 15%, more typically less than about 10% and, still more typically,from about 1% to about 5%. In the case of soy protein isolates, thehydrolyzed soy protein material typically comprises a partiallyhydrolyzed isolate having a degree of hydrolysis of from about 1% toabout 5%.

Suitable methods for hydrolysis of soy protein sources include acidhydrolysis and caustic hydrolysis. Soy protein sources (e.g., a soyprotein isolate) may also be hydrolyzed by treatment of the materialwith an enzyme such as a protease obtained from a plant or microbialsource; for example, contacting the isolate with a protease at a pH offrom about 7 to about 8. Suitable proteolytic enzymes include bromelinand papain. It is currently believed that proteolytic hydrolysis attackscertain peptide bonds, thereby reducing the molecular weights of certainproteins present in the proteins in the feed mixture.

The viscosity and/or gelling properties of dairy whey protein may alsobe modified by partial hydrolysis. Hydrolysis may be carried out by, forexample, treating the dairy whey protein with a proteolytic enzyme.Suitable proteolytic enzymes include, for example, bromelin, papain, andrennin.

Gel strength, expressed in terms of the extent of gelation (G) may bedetermined by preparing a slurry (commonly 200 grams of a slurry havinga 1:5 weight ratio of soy protein, dairy protein, and mixtures thereofsource to water) to be placed in an inverted frustoconical containerwhich is placed on its side to determine the amount of the slurry thatflows from the container. The container has a capacity of approximately150 ml (5 ounces), height of 7 cm, top inner diameter of 6 cm, and abottom inner diameter of 4 cm. The slurry sample of the soy proteinand/or dairy protein source may be formed by cutting or chopping the soyprotein and/or dairy protein source with water in a suitable food cutterincluding, for example, a Hobart Food Cutter manufactured by HobartCorporation (Troy, Ohio). The extent of gelation, G, indicates theamount of slurry remaining in the container over a set period of time.Low viscosity/low gelling sources of soy protein and/or dairy proteinsuitable for use in accordance with the present invention typicallyexhibit an extent of gelation, on a basis of 200 grams of sampleintroduced to the container and taken five minutes after the containeris placed on its side, of from about 1 to about 80 grams (i.e., fromabout 1 to about 80 grams, 0.5% to about 40%, of the slurry remains inthe container five minutes after the container is placed on its side).High viscosity/medium to high gelling sources of soy protein and/ordairy protein suitable for use in accordance with the present inventiontypically exhibit an extent of gelation, on the same basis describedabove, of from about 45 to about 140 grams (i.e., from about 45 to about140 grams, 22% to about 70%, of the slurry remains in the container fiveminutes after the container is placed on its side). A blend of sourcescomprising a low viscosity/low gelling source and a high viscosity/highgelling source typically have a gelation rate, on the same basis, offrom about 20 to about 120 grams.

In accordance with one embodiment of the present invention, a lowviscosity/low gelling source is preferably combined with a highviscosity/high gelling source to form the blend. The presence of thehigh viscosity/high gelling source reduces the risk of excessiveexpansion of the blend upon extrusion, provides a honeycomb structure tothe extrudate, and generally contributes stability to the blend. The lowviscosity/low gelling and high viscosity/high gelling sources can becombined in varying proportions depending on the desired characteristicsof the extrudate.

In a preferred embodiment, the protein-containing feed mixture typicallycomprises a blend of soy protein isolates, dairy protein and mixturesthereof comprising at least about 2 parts by weight of a hydrolyzed(i.e., generally low viscosity/low gelling) soy protein isolate, dairyprotein and mixtures thereof per part by weight of an unhydrolyzed(i.e., generally high viscosity/high gelling) soy protein isolate, dairyprotein and mixtures thereof, more typically at least about 3 parts byweight of a hydrolyzed soy protein isolate, dairy protein and mixturesthereof per part by weight of an unhydrolyzed soy protein isolate, dairyprotein and mixtures thereof and, still more typically, at least about 4parts by weight of a hydrolyzed soy protein isolate, dairy protein andmixtures thereof per part by weight of an unhydrolyzed soy proteinisolate, dairy protein and mixtures thereof. Preferably, the blend ofsoy protein isolates, dairy protein and mixtures thereof comprises fromabout 2 parts by weight to about 8 parts by weight of a hydrolyzed soyprotein isolate, dairy protein and mixtures thereof per part by weightof an unhydrolyzed soy protein isolate, dairy protein and mixturesthereof. More preferably, the blend of soy protein isolates, dairyprotein and mixtures thereof comprises from about 4 parts by weight toabout 6 parts by weight of a hydrolyzed soy protein isolate, dairyprotein and mixtures thereof per part by weight of an unhydrolyzed soyprotein isolate, dairy protein and mixtures thereof.

Blends comprising a plurality of soy protein isolates, dairy protein andmixtures thereof, one of which is a low viscosity/low gelling sourceproduced by partial hydrolysis of a soy protein isolate, dairy proteinand mixtures thereof typically comprise from about 60% to about 100% byweight of a hydrolyzed soy protein isolate, dairy protein and mixturesthereof on a moisture-free basis and from about 0% to about 33% byweight of an unhydrolyzed soy protein isolate, dairy protein andmixtures thereof on a moisture-free basis. More typically, such blendscomprise from about 60% to about 90% by weight of a hydrolyzed soyprotein isolate, dairy protein and mixtures thereof on a moisture-freebasis and from about 0% to about 20% by weight of an unhydrolyzed soyprotein isolate, dairy protein and mixtures thereof on a moisture-freebasis. More typically, such blends comprise from about 60% to about 90%by weight of a hydrolyzed soy protein isolate, dairy protein andmixtures thereof on a moisture-free basis and from about 5% to about 20%by weight of an unhydrolyzed soy protein isolate, dairy protein andmixtures thereof on a moisture-free basis. Still more typically, suchblends comprise from about 65% to about 85% by weight of a hydrolyzedsoy protein isolate, dairy protein and mixtures thereof on amoisture-free basis and from about 10% to about 20% by weight of anunhydrolyzed soy isolate, dairy protein and mixtures thereof on amoisture-free basis. Even more typically, such blends comprise fromabout 65% to about 75% by weight of a hydrolyzed soy protein isolate,dairy protein and mixtures thereof on a moisture-free basis and fromabout 15% to about 20% by weight of an unhydrolyzed soy protein isolate,dairy protein and mixtures thereof on a moisture-free basis. Withrespect to certain protein sources (e.g., casein) higher ratios ofunhydrolyzed to hydrolyzed protein are acceptable, up to and including100% casein.

Suitable isolated soy protein sources exhibiting a low viscosity and/orlow gelling (i.e., partially hydrolyzed) for use as a low viscosity/lowgelling soy protein material include SUPRO® 670, SUPRO® 710, and SUPRO®8000 available from The Solae Company (St. Louis, Mo.), and PROFAM 931and PROFAM 873 available from Archer Daniels Midland (Decatur, Ill.).For SUPRO® 670, SUPRO® 710, and SUPRO® 8000 the degree of hydrolysis canrange from 0.5%-5.0%. The molecular weight distribution of each of theseisolates can be determined by size exclusion chromatography.

Suitable sources of high viscosity and/or medium/high gelling isolatedsoy protein (i.e., unhydrolyzed) for use as the second soy proteinisolate include SUPRO® 620, SUPRO® 500E, SUPRO® 630, and SUPRO® EX33available from The Solae Company (St. Louis, Mo.); PROFAM 981 availablefrom Archer Daniels Midland (Decatur, Ill.); and PROLISSE soy proteinisolate available from Cargill Soy Protein Solutions, Inc. (Minneapolis,Minn.).

Table 1 provides molecular weight distributions for certain of thecommercial SUPRO® products mentioned above. TABLE 1 Estimated MolecularWeight Distribution of SUPRO ® products determined at an absorbance of280 nm using HPLC-SEC (High Performance Liquid Chromatography - SizeExclusion Chromatography) gel filtration in 6M guanidine HCl.Product >50,000 20,000-50,000 5000-20,000 2000-5000 SUPRO ® 620 21%  44%30%  5% SUPRO ® 670 7% 17% 55% 21% SUPRO ® 710 2% 12% 55% 31%

Suitable sources for soy protein when preparing the protein extrudatecontaining 100% unhydrolyzed soy protein include SUPRO® 620, SUPRO®500E, SUPRO® 630, and SUPRO® EX33 available from The Solae Company (St.Louis, Mo.); PROFAM 981 available from Archer Daniels Midland (Decatur,Ill.); and PROLISSE soy protein isolate available from Cargill SoyProtein Solutions, Inc. (Minneapolis, Minn.).

Rice flour, Fibrim, and soy lecithin powder can be added to controlexpansion of the protein extrudate.

Suitable sources of dairy protein include calcium caseinate, sodiumcaseinate, whey protein isolates, whey protein concentrates, andmixtures thereof. In particular, whey protein isolates can be Bipro orBiozate 3 available from Davisco Foods, Inc. (Eden Prairie, Minn.). Wheyprotein concentrate can be WPC80 obtained from Farbest Brands (PlainCity, Ohio).

The color intensity of the protein extrudate can be adjusted using cocoapowder, caramel, and mixtures thereof Increasing the amount of cocoapowder and/or caramel yields darker, more intensely colored nuggets.Cocoa is added to the protein-containing feed mixture in the form ofcocoa powder. Typically, the protein-containing feed mixture comprisesfrom about 1% to about 8% by weight cocoa powder on a moisture-freebasis. (Moisture-free basis and dry basis are used interchangeablythroughout the Specification.) Any cocoa powder may be used, such asCocoa Powder from Bloomer Chocolate (Chicago, Ill.) and ADM Cocoa,Archer Daniels Midland (Decatur, Ill.).

Color intensity of the protein extrudate is measured using acolor-difference meter such as a Hunterlab colorimeter to obtain a colorL value, a color A value, and a color B value. Because the method ismeasuring the color of an irregular shaped surface, a minimum of six (6)separate color measurements are taken and averaged to obtain consistentresults.

The scientific basis for the measurement of color is the existence ofthree different color-response mechanisms in the human eye. The spectralresponses of these light-receiving devices to different wave lengths arewell known. In order to quantify a color stimulus, the responses of thecolor sensing devices to different wave lengths have been standardizedinto a table called the CIE Standard Observer.

The Hunterlab calorimeter is a tristimulus instrument that measurescolor in L, A, and B values by using a filter that spectrallyapproximates the CIE Standard Observer functions of the eye. The L, A,and B scales give measurements of color in visual units of colorperception that relate to perceived color and color difference. Thecolor “L” scale measures lightness and varies from 100 for perfect whiteto zero for black; the color “A” scale measures redness when positiveand greenness when negative; and the color “B” scale measures yellownesswhen positive and blueness when negative.

When using the Hunterlab colorimeter, first the L, A and B scales of thecalorimeter are checked with the white calibration tile. Next, theinstrument is standardized using the black glass and white tile. Thesample cup is checked for any imperfections. The sample cup is thenfilled with the nuggets until the cup is about ½ to ¾ full. The filledsample cup is placed over the instrument measuring port (light source).The cup should be centered over the light source. The sample cup iscovered with the sample cover. The nugget samples are measured for color(L, A, and B) six (6) times and then averaged. Discard the nugget sampleand repeat the steps until all 6 samples have been run. The Hunterlabcalorimeter will then display the average values for L, A, and B. The L,A, and B scale values obtained for the nugget sample are reported as thesample color. The control sample must be a soy protein isolate nuggethaving a color value (L, A, and B values) within the range of the samplebeing evaluated. It must be a well mixed sample and kept in an airtightcontainer at room temperature. The mean value established for thecontrol is obtained by averaging the results of 24 separate trials. Thisdata is generated by evaluating the sample six (6) separate times onfour (4)different days. The control sample is to be evaluated once every8 hours. If the control is not within the established range(mean±standard deviation); check the L, A, and B scales with whitecalibration tile. If the colorimeter is calibrated according to thecalibration tile, stop routine testing and investigate possiblevariables that could effect results such as: 1. Zero scale adjustment;2. Source lamp; 3. Dirty or damaged calibration tiles; and 4. Establisha new control every 12 months.

The protein-containing feed mixture may also contain one or more solublecarbohydrate sources in an amount of from about 0.001% to about 20% byweight soluble carbohydrates on a moisture-free basis. Typically, theprotein-containing feed mixture comprises from about 0% to about 10% byweight soluble carbohydrates on a moisture-free basis. Suitable sourcesof soluble carbohydrates include, for example, cereals, tubers and rootssuch as rice (e.g., rice flour), wheat, corn, barley, potatoes (e.g.,native potato starch), and tapioca (e.g., native tapioca starch).

In addition to soluble carbohydrates, the feed mixture may also containinsoluble carbohydrate such as soy fiber which does not contribute tonutritive carbohydrate load and which, generally, is present as an aidin processing of the mixture because the fiber serves to facilitateflowability and expansion of the feed mixture. When soy fiber is presentin the mixture to serve either as filler to increase the volume of themixture or as a processing aid, the amount of fiber present can varywidely. Generally, however, the feed mixture comprises from about 0.001%to about 5% by weight fiber and, more generally, from about 1% to about3% by weight fiber. Soy fiber absorbs moisture as the extrusion massflows through the extrusion barrel to the die. A modest concentration ofsoy fiber is believed to be effective in obstructing cross-linking ofprotein molecules, thus preventing excessive gel strength fromdeveloping in the cooked extrusion mass exiting the die. Unlike theprotein, which also absorbs moisture, soy fiber readily releasesmoisture upon release of pressure at the die exit temperature. Flashingof the moisture released contributes to expansion, i.e., “puffing,” ofthe extrudate, thus conducing to the formation of the low densityextrudate of the invention.

Referring now to FIG. 1, one embodiment of the process of the presentinvention is shown. The process comprises introducing the particularingredients of the protein-containing feed mixture formulation into amixing tank 101 (i.e., an ingredient blender) to combine the ingredientsand form a protein feed pre-mix. The pre-mix is then transferred to ahopper 103 where the pre-mix is held for feeding via screw feeder 105 toa pre-conditioner 107 to form a conditioned feed mixture. Theconditioned feed mixture is then fed to an extrusion apparatus (i.e.,extruder) 109 in which the feed mixture is heated under mechanicalpressure generated by the screws of the extruder to form a moltenextrusion mass. The molten extrusion mass exits the extruder through anextrusion die.

In pre-conditioner 107, the particulate solid ingredient mix ispreheated, contacted with moisture, and held under controlledtemperature and pressure conditions to allow the moisture to penetrateand soften the individual particles. The preconditioning step increasesthe bulk density of the particulate feed mixture and improves its flowcharacteristics. The preconditioner 107 contains one or more paddles topromote uniform mixing of the feed and transfer of the feed mixturethrough the preconditioner. The configuration and rotational speed ofthe paddles vary widely, depending on the capacity of thepreconditioner, the extruder throughput and/or the desired residencetime of the feed mixture in the preconditioner or extruder barrel.Generally, the speed of the paddles is from about 500 to about 1300revolutions per minute (rpm).

Typically, the protein-containing feed mixture is pre-conditioned priorto introduction into the extrusion apparatus 109 by contacting a pre-mixwith moisture (i.e., steam and/or water) at a temperature of at leastabout 45° C. (110° F.). More typically, the feed mixture is conditionedprior to heating by contacting a pre-mix with moisture at a temperatureof from about 45° C. (110° F.) to about 85° C. (185° F.) feed mixture isconditioned prior to heating by contacting a pre-mix with moisture at atemperature of from about 45° C. (110° F.) to about 70° C. (160° F.). Ithas been observed that higher temperatures in the preconditioner mayencourage starches to gelatinize, which in turn may cause lumps to formwhich may impede flow of the feed mixture from the preconditioner to theextruder barrel.

Typically, the pre-mix is conditioned for a period of about 30 to about60 seconds, depending on the speed and the size of the conditioner. Moretypically, the pre-mix is conditioned for a period of from about 40 toabout 50 seconds, most typically about 45 seconds. The pre-mix iscontacted with steam and/or water and heated in the pre-conditioner 107at generally constant steam flow to achieve the desired temperatures.The water and/or steam conditions (i.e., hydrates) the feed mixture,increases its density, and facilitates the flowability of the dried mixwithout interference prior to introduction to the extruder barrel wherethe proteins are texturized. In certain embodiments, the feed mixturepre-mix is contacted with both water and steam to produce a conditionedfeed mixture. For example, experience to date suggests that it may bepreferable to add both water and steam to increase the density of thedry mix as steam contains moisture to hydrate the dry mix and alsoprovides heat which promotes hydration of the dry mix by the water.

The conditioned pre-mix may contain from about 5% to about 25% by weightwater. Preferably, the conditioned pre-mix contains from about 5% toabout 15% by weight water. The conditioned pre-mix typically has a bulkdensity of from about 0.25 g/cm³ to about 0.6 g/cm³. Generally, as thebulk density of the pre-conditioned feed mixture increases within thisrange, the feed mixture is easier to process. This is presently believedto be due to such mixtures occupying all or a majority of the spacebetween the screws of the extruder, thereby facilitating conveying theextrusion mass through the barrel.

The conditioned pre-mix is generally introduced to the extrusionapparatus 109 at a rate of no more than about 10 kilograms (kg)/min (nomore than about 20 lbs/min). Typically, the conditioned pre-mix isintroduced to the barrel at a rate of from about 2 to about 10 kg/min(from about 5 to about 20 lbs/min), more typically from about 5 to about10 kg/min (from about 10 to about 20 lbs/min) and, still more typically,from about 6 to about 8 kg/min (from about 12 to about 18 lbs/min).Generally, it has been observed that the density of the extrudatedecreases as the feed rate of pre-mix to the extruder increases. Theresidence time of the extrusion mass in the extruder barrel is typicallyless than about 60 seconds, more typically less than about 30 secondsand, still more typically, from about 15 to about 30 seconds.

Typically, extrusion mass passes through the barrel at a rate of fromabout 7.5 kg/min to about 40 kg/min (from about 17 lbs/min to about 85lbs/min). More typically, extrusion mass passes through the barrel at arate of from about 7.5 kg/min to about 30 kg/min (from about 17 lbs/min65 lbs/min). Still more typically, extrusion mass passes through thebarrel at a rate of from about 7.5 kg/min to about 22 kg/min (from about17 lbs/min to about 50 lbs/min). Even more typically, extrusion masspasses through the barrel at a rate of 7.5 kg/min to about 15 kg/min(from about 17 lbs/min to about 35 lbs/min).

Various extrusion apparatus suitable for forming a molten extrusion massfrom a feed material comprising vegetable protein, dairy protein, ormixtures thereof are well known in the art. One suitable extrusionapparatus is a double-barrel, twin screw extruder as described, forexample, in U.S. Pat. No. 4,600,311. Examples of commercially availabledouble-barrel, twin screw extrusion apparatus include a CLEXTRAL ModelBC-72 extruder manufactured by Clextral, Inc. (Tampa, Fla.) having anL/D ratio of 13.5:1 and four heating zones; a WENGER Model TX-57extruder manufactured by Wenger (Sabetha, Kans.) having an L/D ratio of14:1 and four heating zones; and a WENGER Model TX-52 extrudermanufactured by Wenger (Sabetha, Kans.) having an L/D ratio of 14:1 andfour heating zones. Other suitable extruders include CLEXTRAL ModelsBC-82 and BC-92 and WENGER Models TX-138, TX-144, TX-162, and TX-168.

The ratio of the length and diameter of the extruder (L/D ratio)generally determines the length of extruder necessary to process themixture and affects the residence time of the mixture therein. Generallythe L/D ratio is greater than about 10: 1, greater than about 15:1,greater than about 20:1, or even greater than about 25:1.

The screws of a twin screw extruder can rotate within the barrel in thesame or opposite directions.

Rotation of the screws in the same direction is referred to as singleflow whereas rotation of the screws in opposite directions is referredto as double flow.

The speed of the screw or screws of the extruder may vary depending onthe particular apparatus.

However, the screw speed is typically from about 250 to about 350revolutions per minute (rpm), more typically from about 250 to about 335rpm and, still more typically, from about 270 to about 305 rpm.Generally, as the screw speed increases, the density of the extrudatesdecreases.

The extrusion apparatus 109 generally comprises a plurality of heatingzones through which feed mixture is conveyed under mechanical pressureprior to exiting the extrusion apparatus 109 through an extrusion die.The temperature in each successive heating zone generally exceeds thetemperature of the previous heating zone by between about 10° C. andabout 70° C. (between about 15° F. and about 125° F.), more generally bybetween about 10° C. and about 50° C. (from about 15° F. to about 90°F.) and, more generally, from about 10° C. to about 30° C. (from about15° F. to about 55° F.).

Typically, the temperature in the last heating zone is from about 90° C.to about 150° C. (from about 195° F. to about 300° F.), more typicallyfrom about 100° C. to about 150° C. (from about 212° F. to about 300°F.) and, still more typically, from about 100° C. to about 130° C. (fromabout 210° F. to about 270° F.).

Typically, the temperature in the next to last heating zone is fromabout 80° C. to about 120° C. (from about 175° C. to about 250° C.) and,more typically, from about 90° C. to about 110° C. (from about 195° F.to about 230° F.).

Typically, the temperature in the heating zone immediately before thenext to last heating zone is from about 70° C. to about 100° C. (fromabout 160° F. to about 210° F.) and, more typically, from about 80° C.to about 90° C. (from about 175° F. to about 195° F.).

Typically, the temperature in the heating zone separated from the lastheating zone by two heating zones is from about 60° C. to about 90° C.(from about 140° F. to about 195° F.) and, more typically, from about70° C. to about 80° C. (from about 160° F. to about 175° F.).

Typically, the extrusion apparatus comprises at least about threeheating zones and, more typically, at least about four heating zones. Ina preferred embodiment, the conditioned pre-mix is transferred throughfour heating zones within the extrusion apparatus, with the feed mixtureheated to a temperature of from about 100° C. to about 150° C. (fromabout 212° F. to about 302° F.) such that the molten extrusion massenters the extrusion die at a temperature of from about 100° C. to about150° C. (from about 212° F. to about 302° F.).

In such an embodiment, the first heating zone is preferably operated ata temperature of from about 60° C. to about 90° C. (from about 140° F.to about 195° F.), the second heating zone is operated at a temperatureof from about 70° C. to about 100° C. (from about 160° F. to about 212°F.), the third heating zone is operated at a temperature of from about80° C. to about 120° C. (from about 175° F. to about 250° F.) and thefourth heating zone is operated at a temperature of from about 90° C. toabout 150° C. (from about 195° F. to about 302° F.).

The temperature within the heating zones may be controlled usingsuitable temperature control systems including, for example, Mokontemperature control systems manufactured by Clextral (Tampa, Fla.).Steam may also be introduced to one or more heating zones via one ormore valves in communication with the zones to control the temperature.

Apparatus used to control the temperature of the heating zones may beautomatically controlled. One such control system includes suitablevalves (e.g., solenoid valves) in communication with a programmablelogic controller (PLC).

The pressure within the extruder barrel is not narrowly critical.Typically the extrusion mass is subjected to a pressure of at leastabout 400 psig (about 28 bar) and generally the pressure within the lasttwo heating zones is from about 1000 psig to about 3000 psig (from about70 bar to about 210 bar). The barrel pressure is dependent on numerousfactors including, for example, the extruder screw speed, feed rate ofthe mixture to the barrel, feed rate of water to the barrel, and theviscosity of the molten mass within the barrel.

The heating zones within the barrel may be characterized in terms of theaction upon the mixture therein. For example, zones in which the primarypurpose is to convey the mixture longitudinally along the barrel aregenerally referred to as “conveying zones” and zones in which theprimary purpose is mixing are generally referred to as “mixing zones.”Zones in which the primary purpose is to compress the mixture aregenerally referred to as “compression zones” and zones in which theprimary purpose is to provide shearing of the proteins are referred toas “shearing zones.” It should be understood that more than one actionmay occur within a zone; for example, there may be“shearing/compression” zones or “mixing/shearing” zones. The action uponthe mixture within the various zones is generally determined by variousconditions within the zone including, for example, the temperature ofthe zone and the screw profile within the zone.

The extruder is characterized by its screw profile which is determined,at least in part, by the length to pitch ratio of the various portionsof the screw. Length (L) indicates the length of the screw while pitch(P) indicates the distance required for 1 full rotation of a thread ofthe screw. In the case of a modular screw containing a plurality ofscrew portions having varying characteristics, L can indicate the lengthof such a portion and P the distance required for 1 full rotation of athread of the screw. The intensity of mixing, compression, and/orshearing generally increases as the pitch decreases and, accordingly,L:P increases. L:P ratios for the twin-screws within the various heatingzones of one embodiment of the present invention are provided below inTable 2. TABLE 2 Zone L:P Flow Conveying 200/100 Double flow Conveying200/100 Double flow Conveying 150/100 Double flow Compression 200/66Double flow Compression 200/66 Double flow Shearing 100/50 Double flowShearing 100/40 Single flow Shearing 100/30 (reverse) Single flow

Water is injected into the extruder barrel to hydrate the feed mixtureand promote texturization of the proteins. As an aid in forming themolten extrusion mass the water may act as a plasticizing agent. Watermay be introduced to the extruder barrel via one or more injection jetsin communication with a heating zone. Typically, the mixture in thebarrel contains from about 15% to about 30% by weight water. The rate ofintroduction of water to any of the heating zones is generallycontrolled to promote production of an extrudate having desiredcharacteristics. It has been observed that as the rate of introductionof water to the barrel decreases, the density of the extrudatedecreases. Typically, less than about 1 kg of water per kg of proteinare introduced to the barrel and, more typically less than about 0.5 kgof water per kg of protein and, still more typically, less than about0.25 kg of water per kg of protein are introduced to the barrel.Generally, from about 0.1 kg to about 1 kg of water per kg of proteinare introduced to the barrel.

Referring again to FIG. 1, the molten extrusion mass in extrusionapparatus 109 is extruded through a die (not shown) to produce anextrudate, which is then dried in dryer 111.

Extrusion conditions are generally such that the product emerging fromthe extruder barrel typically has a moisture content of from about 20%to about 45% by weight wet basis and, more typically, from about 30% toabout 40% by weight wet basis. The moisture content is derived fromwater present in the mixture introduced to the extruder, moisture addedduring preconditioning and/or any water injected into the extruderbarrel during processing.

Upon release of pressure, the molten extrusion mass exits the extruderbarrel through the die, superheated water present in the mass flashesoff as steam, causing simultaneous expansion (i.e., puffing) of thematerial. The level of expansion of the extrudate upon exiting ofmixture from the extruder in terms of the ratio of the cross-sectionalarea of extrudate to the cross-sectional area of die openings isgenerally less than about 15:1, more generally less than about 10:1 and,still more generally, less than about 5:1. Typically, the ratio of thecross-sectional area of extrudate to the cross-sectional area of dieopenings is from about 2:1 to about 11:1 and, more typically, from about2:1 to about 10:1.

The extrudate is cut after exiting the die. Suitable apparatus forcutting the extrudate include flexible knives manufactured by Wenger(Sabetha, Kans.) and Clextral (Tampa, Fla.).

The dryer 111 used to dry the extrudates generally comprises a pluralityof drying zones in which the air temperature may vary. Generally, thetemperature of the air within one or more of the zones will be fromabout 135° C. to about 185° C. (from about 280° F. to about 370° F.).Typically, the temperature of the air within one or more of the zones isfrom about 140° C. to about 180° C. (from about 290° F. to about 360°F.), more typically from about 155° C. to 170° C. (from about 310° F. to340° F.) and, still more typically, from about 160° C. to about 165° C.(from about 320° F. to about 330° F.). Typically, the extrudate ispresent in the dryer for a time sufficient to provide an extrudatehaving a desired moisture content. This desired moisture content mayvary widely depending on the intended application of the extrudate and,typically, is from about 2.5% to about 5.0% by weight. Generally, theextrudate is dried for at least about 5 minutes and, more generally, forat least about 10 minutes. Suitable dryers include those manufactured byWolverine Proctor & Schwartz (Merrimac, Mass.), National DryingMachinery Co. (Philadelphia, Pa.), Wenger (Sabetha, Kans.), Clextral(Tampa, Fla.), and Buehler (Lake Bluff, Ill.).

The extrudates may further be comminuted to reduce the average particlesize of the extrudate. Suitable grinding apparatus include hammer millssuch as Mikro Hammer Mills manufactured by Hosokawa Micron Ltd.(England).

Preferably, the novel protein extrudates of the present inventioncomprise at least about 70% by weight protein on a moisture-free basis,more preferably at least about 80% by weight protein on a moisture-freebasis and, still more preferably, at least about 90% by weight proteinon a moisture-free basis. In one preferred embodiment, the proteinextrudate comprises from about 80% to about 95% by weight protein on amoisture-free basis.

The protein extrudates comprise vegetable protein, dairy protein, andmixtures thereof and may also include other components including fiber(e.g., soy fiber and cereal fiber), carbohydrates (e.g., complexcarbohydrates such as starches), and water. Preferably, a majority ofthe protein in the food product comprises soy proteins, dairy proteins,and mixtures thereof and, preferably, the source of a majority of theprotein in the extrudate is one or more soy protein isolates, dairyproteins, and mixtures thereof. The dairy proteins include calciumcaseinate, sodium caseinate, whey protein concentrate, whey proteinisolate, and mixtures thereof.

In one embodiment, the protein extrudate is in the form of a low densitysnack product including a majority solids component and a watercomponent. Typically, such products include between about 25% and about95% protein on a majority solids component and water component basis.

In another embodiment, the protein extrudate is in the form a lowdensity, low moisture content proteinaceous food product comprising aprincipal solid component which includes protein in a concentration ofbetween about 25% and about 95% by weight of the water present in theproduct and the dry basis weight of the principal solid component. Inone variation of this embodiment, the principal solid component is inthe form of a proteinaceous solid matrix and, in another, aproteinaceous solid extrudate.

Generally, the protein extrudates of the present invention have adensity of from about 0.1 g/cm³ to about 0.4 g/cm³. Preferably, theprotein extrudates of the present invention have a density of from about0.15 g/cm³ to about 0.35 g/cm³. In such embodiments, the density of theextrudate may be from about 0.20 g/cm³ to about 0.27 g/cm³, from about0.24 g/cm³ to about 0.27 g/cm³, or from about 0.27 g/cm³ to about 0.32g/cm³.

Low density snack food products prepared in accordance with the presentinvention generally have a density of from about 0.02 g/cm³ to about 0.7g/cm³ and, more generally, from about 0.02 g/cm³ to about 0.5 g/cm³.Generally, such extrudates exhibit a crisp, non-fibrous eating texture.In certain embodiments, the products have a density of from about 0.02g/cm³ to about 0.1 g/cm³ or even from about 0.02 g/cm³ to about 0.05g/cm³. Low density, low moisture content proteinaceous food productscomprising a principal solid component typically exhibit such densities.

In a preferred embodiment, the protein extrudates of the presentinvention comprise hydrolyzed soy protein and unhydrolyzed soy proteinas described above. Typically, the protein extrudate comprises at leastabout 1 part by weight hydrolyzed soy protein per part by weightunhydrolyzed soy protein and, more preferably at least 2 parts by weighthydrolyzed soy protein per part by weight unhydrolyzed soy protein.

More typically, the protein extrudate comprises from about 2 to about 8parts by weight hydrolyzed soy protein per part by weight unhydrolyzedsoy protein, from about 2 to about 4 parts by weight hydrolyzed soyprotein per part by weight unhydrolyzed soy protein, or from about 4 toabout 6 parts by weight hydrolyzed soy protein per part by weightunhydrolyzed soy protein.

In certain embodiments, the food product includes hydrolyzed soy proteinand at least partially hydrolyzed soy protein isolates and unhydrolyzedsoy protein (e.g., a soy protein isolate, a soy protein concentrate, orsoy flour) and the partially hydrolyzed protein is present in theproduct in a weight ratio of between 80:20 to 55:45 to the unhydrolyzedsoy protein.

Preferably, the extrudate contains less than about 20% by weightcarbohydrates, more preferably less than about 10% by weightcarbohydrates, still more preferably less than about 5% by weight and,even more preferably, from about 2% to about 5% by weight carbohydrates.

Carbohydrate (i.e., starch) present in the feed mixture typically formsmicroparticles of starch gels under the conditions of the extruderbarrel caused by denaturing of starches. Thus, the starch present ispartially gelatinized. The degree of starch gelatinization of the starchportions of the extrudate may be determined by a starch iodine test orby polarized microscopy. Typically, the starch present in the extrudateexhibits a degree of gelatinization of from about 70% to about 90%.While the starch is not present in an amount sufficient to provide agelatinous character to the extrudate, its degree of gelatinization canbe used as a measure of the degree of “cooking” of the extrusion masswithin the barrel as generally increased temperatures are necessary forgelatinization of starches.

Typically, the extrudates contains from about 0.001% to about 5% byweight fiber on a moisture free basis and, more typically, from about 1%to about 3% by weight fiber on a moisture free basis. Fiber in theextrusion mass aids in expansion of the extrusion mass as it exits theextrusion die. It is presently believed that fiber in the extrusion massdisrupts formation of bonds between proteins which generally form amatrix which tends to trap water present in the mixture and preventexpansion. This disruption of bond formation and the natural tendency ofthe fiber to release water facilitates flashing of water from theextrusion mass as steam and expansion of the extrusion mass.

In addition to protein, the majority solids component or principal solidcomponent of food products of the present invention may comprise othersolid components (i.e., fillers) such as carbohydrates or fibers. Theproduct may include filler in a ratio of filler to protein in the rangeof from about 5:95 to about 75:25. In certain embodiments, a majority ofthe filler is starch. Suitable starches include rice flour, potato,tapioca, and mixtures thereof.

Generally, water is present in the dried extrudate at a concentration offrom about 2% to about 5.5% by weight. The amount of water may varydepending on other characteristics of the extrudate (e.g., carbohydratecontent and density).

Low density food products of the present invention including a majoritysolids component or a principal solid component typically contain waterat a concentration of between about 1% and about 7% by weight ofprotein, filler, and water and, more typically, between about 3% andabout 5% by weight of protein, filler, and water.

The protein extrudates comprised of soy protein, dairy protein andmixtures thereof disclose a variety of protein combinations. The mainingredient for the combination of soy protein isolate and whey proteinis the soy protein isolate SUPRO® 8000 (The Solae Company, St. Louis,Mo.), which is a hydrolyzed soy protein isolate. Soy protein isolate andnative tapioca starch are used to help create expansion in theextrudates and obtain the desired product density. These ingredientsrelease the water trapped during the extrusion cooking process; theshrinkage ratio when the water is released in the form of steam isminimized when soy protein isolate and native tapioca starch are in theformula, they form larger cells in product structure. The larger cells,change the concentration of cells and increases the air space in producttexture. The result is lower density products.

Whey protein concentrate and whey protein isolates, inhibit expansion inextrusion. They release the water trapped as a consequence of change inpressure, but the shrinkage and elasticity of the extrudates reduces thetexture cell size; it makes products that are denser and crispier.

Dicalcium phosphate and soy lecithin powder function also to modify thecell structure in final products and they help improve the flow abilityof the process.

The protein extrudates of the present invention may further becharacterized as having a hardness of at least about 1000 grams.Typically, the protein extrudates have a hardness of from about 1000 toabout 50,000 grams and, more typically, from about 30,000 to about45,000 grams. The hardness of the extrudates is generally determined byplacing an extrudate sample in a container and crushing the sample witha probe. The force required to break the sample is recorded; the forcethat is required to crush the sample based on its size or weight isproportional to the hardness of the product. The hardness of theextrudates may be determined using a TA.TXT2 Texture Analyzer having a25 kg load cell, manufactured by Stable Micro Systems Ltd. (England).Extrudates having a chewy texture are preferred in certain embodiments.Generally, such extrudates have a hardness of less than about 40,000grams.

The protein extrudates may exhibit a wide range of particle sizes andmay generally be characterized as an oval or round nugget or pellet. Thefollowing weight percents for characterizing the particle sizes of theextrudates of the present invention are provided on an “as is” (i.e.,moisture-containing) basis.

In certain embodiments, the particle size of the extrudate is such thatfrom about 5% to about 10% by weight of the particles are retained on a6 Mesh Standard U.S. sieve, from about 80% to about 90% by weight of theparticles are retained on an 8 Mesh Standard U.S. sieve, from about 5%to about 10% by weight are retained on a 10 Mesh Standard U.S. sieve,and from about 1% to about 3% by weight of the particles pass through a10 Mesh Standard U.S. Sieve.

Such extrudates typically have a length of from about 3 to about 7 mmand, more typically, about 5 mm. The width of such extrudates istypically from about 0.5 to about 3.5 mm and, more typically, about 2mm.

Extrudates having such particle sizes are shown in the photomicrographsin FIGS. 2 and 3.

Extrudate nuggets having these characteristics may be shredded toproduce a textured soy

protein product such that from about 5% to about 10% by weight of theparticles are retained on a ⅛ inch Standard U.S. sieve, from about 10%to about 20% by weight (typically about 15% by weight) of the particlesare retained on a 6 Mesh Standard U.S. Sieve, from about 60% to about80% by weight (typically 70% by weight) of the particles are retained ona 20 Mesh Standard U.S. Sieve, and from about 3% to about 5% by weightof the particles pass through a 20 Mesh Standard U.S. Sieve. Suchshredded extrudates are shown in FIG. 4.

In other embodiments, the particle size of the extrudate is such thatfrom 5% to about 10% by weight are retained on a 4 Mesh Standard U.S.sieve, from about 60% to about 80% by weight are retained on a 6 MeshStandard U.S. sieve, from about 20% to about 40% by weight are retainedon an 8 Mesh Standard U.S. sieve, and from about 1% to about 3% byweight of the particles pass through a 8 Mesh Standard U.S. Sieve.

Such extrudates typically have a length of from about 6 to about 10 mmand, more typically, about 8 mm. The width of such extrudates istypically from about 2.5 to about 5.5 mm and, more typically, about 4mm.

Extrudates having such particle sizes are shown in the photomicrographsin FIGS. 2, 3, and 5.

Extrudate nuggets having these characteristics may be shredded toproduce a textured soy protein product having a particle size such thatfrom about 10% to about 20% by weight are retained on a ¼ inch StandardU.S. sieve, from about 50% to about 80% by weight (typically about 65%by weight) are retained on a 7 Mesh Standard U.S. sieve, from about 20%to about 50% by weight (typically about 35% by weight) are retained on a16 Mesh Standard U.S. Sieve, and from about 3% to about 5% by weightpass through a 16 Mesh Standard U.S. sieve. Such shredded extrudates areshown in FIG. 4.

In still other embodiments, the particle size of the extrudate is suchthat from 5% to about 10% by weight of the particles are retained on a ½inch Standard U.S. sieve, from about 80% to about 90% by weight of theparticles are retained on a ¼ inch Standard U.S. sieve, and from about1% to about 3% by weight pass through a ¼ inch Standard U.S. Sieve.

Such extrudates typically have a length of from about 7 to about 13 mmand, more typically, about 10 mm. The width of such extrudates istypically from about 4 to about 10 mm and, more typically, about 7.5 mm.Extrudates having such particle sizes are shown in FIG. 2.

The extrudate nuggets described above may be ground to produce apowdered soy protein product. Such powder typically exhibits a particlesize such that from about 2% to about 5% by weight of the powder isretained on a 200 Mesh Standard U.S. Sieve, from about 10% to about 25%by weight of the powder is retained on a 325 Mesh Standard U.S. Sieve,and from about 70% to about 100% by weight (typically about 75% byweight) of the powder passes through a 325 Mesh Standard U.S. Sieve.Ground extrudates are shown in FIG. 4.

The products can also have a wide range of pellet durability index (PDI)values usually on the order of from about 65-99, more preferably fromabout 80-97.

The extrudates of the present invention are suitable for incorporationinto a variety of food products including, for example, food bars andready to eat cereals. Such extrudates may generally be oval or round andmay be also be shredded.

In certain embodiments, the protein extrudate is ground or comminuted asdescribed above to produce a powdered extrudate. Typically, such powderhas an average particle size of less than about 10 μm. More typically,the average particle size of the comminuted extrudate is less than about5 μm and, still more typically, from about 1 to about 3 μm. Suchpowdered extrudates are suitable for incorporation into a variety offood products including, for example, beverages, dairy products (e.g.,soy milk and yogurt), baked products, meat products, soups, and gravies.The protein extrudates can be incorporated in such applications in theform of nuggets or pellets, shredded nuggets or pellets, or powders asdescribed above.

Experience to date suggests that a particle size of less than about 5 μmis particularly desirable in the case of extrudates incorporated intobeverages to prevent a “gritty” taste in the product.

A particularly preferred application in which the protein extrudate ofthe present invention is used, is in emulsified meats. The proteinextrudate product may be used in emulsified meats to provide structureto the emulsified meat, which gives the emulsified meat a firm bite anda meaty texture. The protein extrudate also decreases cooking loss ofmoisture from the emulsified meat by readily absorbing water, andprevents “fatting out” of the fat in the meat so the cooked meat isjuicier.

The meat material used to form a meat emulsion in combination with theprotein extrudate of the present invention is preferably a meat usefulfor forming sausages, frankfurters, or other meat products which areformed by filling a casing with a meat material, or can be a meat whichis useful in ground meat applications such as hamburgers, meat loaf andminced meat products. Particularly preferred meat material used incombination with the protein extrudate includes mechanically debonedmeat from chicken, beef, and pork; pork trimmings; beef trimmings; andpork backfat.

A meat emulsion containing a meat material and the ground proteinextrudate contains quantities of each which are selected to provide themeat emulsion with desirable meat-like characteristics, especially afirm texture and a firm bite.

Typically, the ground protein extrudate is present in the meat emulsionin an amount of from about 0% to about 4% by weight, more typically fromabout 0% to about 3% by weight and, still more typically, from about 1%to about 3% by weight.

Typically, the meat material is present in the meat emulsion in anamount of from about 40% to about 95% by weight, more typically fromabout 50% to about 90% by weight and, still more typically, from about60% to about 85% by weight.

The meat emulsion also contains water, which is typically present in anamount of from about 0% to about 25% by weight, more typically fromabout 0% to about 20% by weight, even more typically from about 0% toabout 15% by weight and, still more typically, from about 0% to about10% by weight.

The meat emulsion may also contain other ingredients that providepreservative, flavoring, or coloration qualities to the meat emulsion.For example, the meat emulsion may contain salt, typically from about 1%to about 4% by weight; spices, typically from about 0.1% to about 3% byweight; and preservatives such as nitrates, typically from about 0.001%to about 0.5% by weight.

The protein extrudate of the present invention may be used in beverageapplications including, for example, acidic beverages. Typically, theground protein extrudate is present in the beverage in an amount of fromabout 0.5% to about 3.5% by weight. The beverages in which the proteinextrudate is incorporated typically contain from about 70% to about 90%by weight water. The beverages typically also contain sugars (e.g.,fructose and sucrose) in an amount of up to about 20% by weight.

Preferred food product formulations are described below in variousformulation examples.

In the case of product for the healthy diet consumer, the dried fonmedproduct has total protein (e.g., hydrolyzed and unhydrolyzed) in therange of between about 25% and 55%, by weight of dried formed product.If a mixture of partially hydrolyzed and unhydrolyzed protein is used,the ratio of at least partially hydrolyzed soy protein isolates, dairyprotein and mixtures thereof to unhydrolyzed or gelling soy protein,dairy protein and mixtures thereof is in the range of between about80:20 to about 55:45 preferably in the range of between about 60:20 toabout 60:45 and most preferably about 60:40. Filler, preferably acarbohydrate such as starch (a complex carbohydrate), is present in therange of between about 50% and 75% by weight of dried formed product.The total moisture content is present as described above coating can beapplied to the dried formed product as described above. Also, theabove-mentioned optional ingredients can also be added, for example,nutrients, flavorants, anti-microbial agents, etc. The total fat contentof the finished product, i.e., the dried formed product with flavoringand additives added thereto is less than about 5% and preferably in therange of between about 0.2% and about 5% by weight of finished product.

In the case of product for the balanced diet consumer, protein ispresent in the range of between about 55% and 70% by weight of driedformed product. If a mixture of partially hydrolyzed and unhydrolyzedsoy protein, dairy protein and mixtures thereof is used, the ratio of atleast partially hydrolyzed soy protein isolates, dairy protein andmixtures thereof to the unhlydrolyzed or gelling soy protein, dairyprotein and mixtures thereof is in the range of between about 80:20 toabout 55:45 and preferably about 70:30. Filler, preferably starch, ispresent in the range of between about 30% and 50% by weight of driedformed product. Typically, balanced diet consumers prefer a higher fatcontent since they view fat as an important element of a balanced diet.In this event, total fat in the finished product is in the range ofbetween about 0.2% and about 20%, and preferably in the range of betweenabout 15% and about 20% by weight of finished product. Most of the fatis preferably added with the coating since it is desirable to not mixthe fat prior to extrusion in with the components of the product thatare extruded. The other ingredients as mentioned for the healthy dietconsumer can also be added to this product category in approximately thesame amounts.

For the high protein diet consumer product, it is preferred to addlittle if any filler in order to increase the protein content and reducethe carbohydrate content which to some consumers is detrimental to ahigh protein diet. For such a product line, the protein is present inthe range of between about 70% and 95% by weight of dried formedproduct. The ratio of at least partially hydrolyzed soy proteinisolates, dairy protein and mixtures thereof to unhydrolyzed or gellingsoy protein, dairy protein and mixtures thereof is in the range ofbetween about 80:20 and about 55:45 and preferably about 70:30. Filler,is kept low and is present in the range of between about 0% and about30%, preferably in the range of between about 5% and about 20% by weightof dried formed product. Fat, can be present in this type of product andwould preferably be added with the coating. Fat is present in the rangeof between about 0.2% and about 30% and preferably in the range ofbetween about 7% and about 20% by weight of finished product. Otheroptional ingredients as discussed above can be added to this type ofproduct in approximately the same amounts.

EXAMPLES

The following examples are simply intended to further illustrate andexplain the present invention. The invention, therefore, should not belimited to any of the details in these examples.

Example 1

This example illustrates the preparation of soy protein nuggetscomprising 70%, 75%, 80%, 85%, and 88% soy protein using various feedmixture formulations.

The feed mixtures are described below in Table 3. TABLE 3 Product 70%75% 80% 85% 88% Feed composition protein protein protein protein proteinSUPRO ® 670 63.6% 68.2% 71.7% 77.3% 100%  SUPRO ® 620 15.9% 17.0% 17.8%19.3% 0% Tapioca starch 18.2% 12.5% 9.0%  3.4% 0% Fibrim   2%   2% 1.2%  0% 0% NaCl  0.3%  0.3% 0.3%   0% 0%

As shown in Table 3, the weight ratio of hydrolyzed to unhydrolyzedisolates is approximately 4:1 in the feed mixtures for preparing the70%, 75%, 80%, and 85% protein nuggets. The 88% protein nuggets areprepared from a feed mixture which did not contain an unhydrolyzedisolate.

The ingredients of each feed mixture are mixed in an ingredient blenderfor 5 to 10 minutes to ensure uniform distribution. The dry feed mixtureis pneumatically conveyed to a volumetric feeder (i.e., hopper) and fedto a pre-conditioning tank at a rate of 6.3 to 7.7 kg/min (14-17 lb/min)in which the dry mix is pre-conditioned with steam and water. Water isintroduced to the pre-conditioner at a rate of 0.2 to 0.7 kg/min(0.5-1.5 lb/min) and steam is injected into a conditioning tank at arate of 0.16 to 0.22 kg/min (0.4-0.5 lb/min or 25-30 lb/hr). The mixturein the pre-conditioner is continuously stirred with a paddle rotating at1300-1500 rpm and the flow of steam is carefully monitored to maintainthe temperature of the protein mixture within the pre-conditionerbetween about 60° and about 70.5° C. (140° F.-159° F.).

The dry mix is then introduced to the inlet of the extruder barrel inletby a conveyor. Conditioned feed mix is introduced into the extruder at arate of 6 to 9 kg/min (13.3 to 20 lb/min) using an extruder screw speedof from 275 to 320 μm.

The extruder used is a double-barrel, twin-screw extruder, CLEXTRALModel BC-72 manufactured by Clextral, Inc. (Tampa, Fla.) having an L/Dratio of 15:1 and four heating zones. The screw profile for the extruderis described in Table 4. TABLE 4 Length Pitch 200 100  200 100  150 100 200 66 200 66 100 50 100 40 100  30**Reverse

Water is introduced into the extruder barrel at a rate of 1.8 to 2.7kg/min (4-6 lb/min) without steam injection. The barrel temperatures arecontrolled with a Mokon temperature control system manufactured byClextral (Tampa, Fla.). The extruder contains 4 heating zones throughwhich the feed mixture passes, the temperature profile of the BC-72extruder is shown in Table 5 below. TABLE 5 Extrusion Pre- ExtrusionExtrusion Extrusion Zone 4 conditioner Zone 1 Zone 2 Zone 3 (Die end)60-71° C. 28-29.5° C. 93-96° C. 132-135° C. 140-146° C. (140-160°(82-85.1° (200-205° (270-275° (284-295° F.) F.) F.) F.) F.)

The conditioned feed mix is cooked in the extruder barrel withmechanical energy generated from the extruder screw rpm/shear andelectrical energy at high temperatures to reach the glass transitiontemperature. At high temperatures, shear, and pressure the feed mixmelts and interacts with water and other ingredients to form a plasticlike material which is then extruded through backup plate having a≦1-inch (25-mm) diameter before passing through an extrusion die.

The extrudates are cut using a 6 bladed knife rotating at 2000-3000 rpmto obtain the product size, density and granulation. The die knife areais ventilated by sparging compressed air (within the cutter guard) toaid face plate cooling/product cutting.

The soy protein nuggets are dried with a Proctor single band conveyordryer at a temperature of from about 145° C. to about 165° C. (295° F.to about 325° F.) for a residence time of 5-7 minutes. The dried soynuggets are sieved using #3 and #8 Sweco sieves to remove the fines.

The hardness of the extrudates is determined using a texture analyzer,Model # TA.TXT2 with a 25 kg load cell manufactured by Stable MicroSystems Ltd. (England). The density and hardness of the various soyprotein extrudates are summarized below in Table 6. TABLE 6 Proteincontent (%) Density (g/cm³) Texture (g) 70 0.235 21680.1 75 0.24723918.7 80 0.256 25230.2 85 0.234 22526.4

The effect of varying certain process conditions for various runs usedto prepare 80% soy protein nuggets are summarized below in Table 7.TABLE 7 Effect of Extruder Screw Speed, Water Feed Rate, and MixtureFeed Rate on Power Required and Density and Texture of 80% Soy ProteinNuggets Barrel Mixture Power Extruder Water Feed Feed required DensityTexture Run RPM (%) Rate (%) Rate (%) (AMPS) (g/cc) (g) 1 90 80 85 800.122 5535.4 2 80 90 85 104 0.2436 25850.6 3 90 90 85 104 0.2216 16706.64 90 90 85 104 0.2278 18138.3 5 80 80 75 80 0.2518 23821.3 6 90 90 75 800.2163 14992.1 7 85 85 80 104 0.237 19387.5 8 80 90 75 80 0.2458 21717.79 90 80 75 85 0.2091 13092.1 10 80 80 85 90 0.2518 24777.1 11 85 85 80104 0.2328 19065.7 12 90 80 75 80 0.2161 12855.7 13 90 80 85 90 0.13316234.8 14 80 80 85 80 0.2444 23395.8 15 90 90 75 80 0.2161 12322.4 16 8090 75 90 0.2728 29065.4 17 80 90 85 85 0.2583 26035.7 18 80 80 75 900.2466 24827

The equivalents of extruder rpm (%), mixture feed rate (%) and extruderbarrel water rate (%) are presented below:

Extruder rpm:

-   80%=267 rpm-   85%=284 rpm-   90%=301 rpm    Extruder Feed Rate:-   75%=15 lb/min-   80%=16 lb/min-   85%=17 lb/min    Extruder Barrel Water Rate:-   80%=4.8 Ib/min-   85%=5.1 lb/min-   90%=5.4 Ib/min

Example 2

This example illustrates the preparation of Soy Protein and Whey Protein(Isolate and Concentrate) nuggets; and combinations of both proteins atdifferent ratios comprising a minimum level of 70% protein in the finalnugget product.

-   Soy Protein Isolate, SUPRO® 8000, from The Solae Company (St. Louis,    Mo.), 88% protein, (as is).-   Whey Protein Isolate BiPro, from Davisco Foods, Inc (Eden Prairie,    Minn.), 90% protein, (as is).-   Whey Protein Concentrate WPC80, from Farbest Brands (Plain City,    Ohio), 78% protein, (as is).-   Native Tapioca Starch, from Avebe Corp. (Princeton, N.J.).-   Dicalcium Phosphate, from Astaris Food Phosphates (Webster Groves,    Mo.).

Soy Lecithin Powder, from The Solae Company (St. Louis, Mo.). TABLE 8Sample Sample Sample Sample Sample Sample Ingredients 1 2 3 4 5 Supro ®8000 ISP 80.0% 70.0% 40.0% 60.0% 20.0% Nat. Tapioca Starch 19.7% 19.7%19.7% 19.7% 19.7% Whey Protein Isolate 0.0% 10.0% 40.0% 20.0% 60.0%Bipro Dicalcium Phosphate 0.3% 0.3% 0.3% 0.3% 0.3%

TABLE 9 Sample Ingredients Sample 6 Sample 7 Sample 8 Sample 9 Sample 10Sample 11 Sample 12 Supro 8000 ISP 80.0% 68.0% 60.0% 79.0% 79.0% 75.0%0.0% Nat. Tapioca Starch 19.7% 18.7% 16.7% 0.0% 0.0% 10.0% 10.0% WheyProt. Conc. WPC80 0.0% 13.0% 23.0% 20.0% 0.0% 15.0% 50.0% Whey ProteinIsolate Bipro 0.0% 0.0% 0.0% 0.0% 20.0% 0.0% 40.0% Dicalcium Phosphate0.3% 0.3% 0.3% 0.5% 0.5% 0.0% 0.0% Soy Lecithin powder 0.0% 0.0% 0.0%0.5% 0.5% 0.0% 0.0%

Samples 1 and 6 contained the same ingredients and amounts.

The following procedure was followed to produce final products (nuggets)compromising a minimum of 70% protein.

Each sample was blended in a horizontal ribbon blender Model TD415(Dodge of Mishawaka, Ind.) with 300 Lb capacity. Each ingredient wasweighted in a scale with 150 Lb capacity and 0.01 Lb sensitivity. Theingredients were added to the blender and blended for 20 minutes toensure uniform distribution.

Each sample was manually fed to the extruder hopper and then each ofSamples 1-5 was fed to the preconditioner at 50 KG/Hr (1.84 Lb/Min) andeach of Samples 6-12 at 55 KG/Hr (2.02 Lb/Min).

No steam was used in the preconditioner for Samples 1-4; steam wasinjected for Sample 5, achieving (60° C.-70° C.) preconditionertemperature. For Samples 6-12 steam was used to achieve temperaturesranging from (43° C.-58° C.); the temperature was measured by athermocouple positioned at the preconditioner discharge.

Water was added to the preconditioner and maintained constant in all thevariables at 5.5 Kg/Hr (0.20 Lb/Min). The residence time of dryformulations in the preconditioner was about 4 minutes.

The preconditioned dry formulations were fed at 50 Kg/Hr and 55 Kg/Hr tothe extruder using a transition to prevent waste, dust and ensureconsistent flow to the extruder.

A Wenger TX-52 twin-screw extruder (13.5/1 L/D ratio) manufactured byWenger Manufacturing Inc. (Sabetha, Kans.) was used for the productionof these products.

Barrel temperatures were maintained about the same in all variables:

Zone 1 feeding (60° C.-70° C.); Zone 2 (80° C.-90° C.); Zone 3 (95°C.-110° C.); and Die head (100° C.-120° C).

The product was cut by a 6 blades cutter at 3000-3200 rpm.

The die used for these experiments is a Y adapter which holds an insertdie holder with one insert with 3 holes (1.5 mm diameter).

The screw configuration used in the example was divided into foursections. The first section was conveying; the second section was mixingand shearing; the third section was compressing; and, the fourth sectionwas shearing and compressing.

Water was pumped into the first section of the extruder at differentrates to obtain uniform nugget type shape products with uniform surface.Extruder screw speed and water rate were the main variables adjusted toobtain the shape and product density (<0.4 g/cc).

Wet density was measured using an 1150 ml metal container. Wet densitywas used as reference to modify processing conditions, in particular,screw speed and/or water rate.

Table 10 shows the correlation of samples to water rate, extruder screwspeed, and wet and dry product density. TABLE 10 Water rate ExtruderScrew Wet Density Dry Density Sample Lb/Min Speed rpm g/cc g/cc Sample 20.54 410 0.288 0.290 Sample 3 0.74 547 0.383 0.377 Sample 4 0.58 5310.356 0.382 Sample 5 0.67 495 0.378 0.399 Sample 1 & 0.45 330-350 0.2230.203 Sample 6 Sample 7 0.50 430 0.266 0.267 Sample 8 0.57 503 0.2930.271 Sample 9 0.79 469 0.335 0.349 Sample 10 0.94 470 0.339 0.355Sample 11 0.65 470 0.248 0.248 Sample 12 0.97 457 0.331 0.338

The product was dried in a continuous single pass Proctor Dryer at 121°C. (250° F.) at different residence times to achieve <5.0% productmoisture. Table 11 shows this information. TABLE 11 Drying information:Dryer Setting Drying Time Product Moisture Sample (1-10) “Min” % Sample2 4.0 22.5 1.82 Sample 3 4.0 22.5 2.79 Sample 4 4.0 22.5 2.42 Sample 54.0 22.5 2.45 Sample 1 & 6.0 16.0 3.37 Sample 6 Sample 7 5.5 17.0 3.08Sample 8 5.5 17.0 3.77 Sample 9 5.5 17.0 4.17 Sample 10 5.5 17.0 3.87Sample 11 5.5 17.0 3.28 Sample 12 5.5 17.0 2.90

After drying the product was packaged and analyzed.

A gated Cox funnel was used to feed the container to minimize humanmanipulation while releasing the sample to a metal pint container inorder to calculate the density; the results are presented in Tables 12and 13.

Color measurements were taken using a LabScan XE Model LSXE (HunterLab;Naperville, Ill.).

Granulation was determined using a Rotap model FX-29 (W. S. Tyler;Mentor, Ohio).

The texture of the protein extrudate product was analyzed using thetexture analysis model TA-XT2i (Texture Technologies Corp; New York,N.Y.).

Moisture analyzer IR120 (Denver Instruments; Goettingen, Germany) wasused to determine moisture content.

The results are shown in Tables 12 and 13. TABLE 12 Sample Sample SampleSample Sample Sample 1 2 3 4 5 Density 0.203 0.290 0.377 0.382 0.399g/cc Color Hunter L value 54.12 57.42 62.18 58.55 66.76 A value 3.212.62 2.34 2.30 1.63 B value 18.81 19.00 20.93 19.40 20.48 Moisture %3.37 1.82 2.79 2.42 2.45 Granulation % On U.S. #4 23.38 0.00 0.00 0.000.47 On U.S. #6 76.08 83.01 0.14 0.82 0.98 On U.S. #8 0.42 16.99 99.7799.15 98.00 Pan 0.12 0.00 0.09 0.03 0.55 Texture Analysis Force (g) 748620051 51158 44306 49568

TABLE 13 Sample Sample 6 Sample 7 Sample 8 Sample 9 Sample 10 Sample 11Sample 12 Density g/cc 0.203 0.267 0.271 0.349 0.355 0.248 0.338 ColorHunter L value 54.12 56.79 58.10 57.69 55.73 56.66 57.94 A value 3.213.13 3.59 3.85 3.63 3.48 3.52 B value 18.81 19.46 21.07 21.57 20.6619.64 25.26 Moisture % 3.37 3.08 3.77 4.17 3.87 3.28 2.90 Granulation %On U.S. #4 23.38 0.17 0.01 0.00 0.00 0.03 0.02 On U.S. #6 76.08 99.5899.78 0.03 0.15 99.04 0.11 On U.S. #8 0.42 0.20 0.17 39.61 43.69 0.8198.11 Pan 0.12 0.05 0.04 60.59 56.33 0.18 1.90 Texture Analysis Force(g) 7486 19571 20774 17353 50081

All the samples described in Tables 12 and 13 were within the densitylimits <0.4 g/cc.

Example 3

Textured soy/calcium caseinate or soy/sodium caseinate and caseinateproducts were prepared at different ratios and protein levels, from 70%to 90% with various dry feed samples as presented in Tables 14 and At70% soy/caseinate textured products, the ratios of soy protein isolate(SPI) to calcium-caseinate, and soy protein isolate to sodium-caseinatein the dry feed samples were 5:1, 2:1, 1:1, and 1:2. The control 70% and80% soy protein texture products had 5:1 ratios of hydrolyzed tounhydrolyzed soy protein isolate in the dry mix samples. The 80% and 90%soy/calcium caseinate or soy/sodium caseinate textured products also had5:1 and 5.67:1 in the dry mix samples. In the 80% and 90% calciumcaseinate or sodium caseinate extruded products, the dry mix had no soyprotein in the samples as presented in Table 15. TABLE 14 Soy andSoy/Caseinate Proteins Formulations with 70% Protein at DifferentRatios. Sample Sample Sample Sample Sample Sample Sample Sample Sample13 14 15 16 17 18 19 20 21 (%) (%) (%) (%) (%) (%) (%) (%) (%) SUPRO ®8000 68.3 68.3 54.7 41.0 27.3 68.3 54.7 41.0 27.3 Supro ® 248 13.7 — — —— — — — — Ca-Caseinate — 13.7 27.3 41.0 54.7 — — — — Na-Caseinate — — —— — 13.7 27.3 41.0 54.7 Tapioca Starch 15.7 15.7 15.7 15.7 15.7 15.715.7 15.7 15.7 Fibrim 2000 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 DicalciumPO₄ 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Salt (NaCl) 0.1 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1

The ingredients for each dry feed mixture were mixed in an EagleVertical blender for 40 minutes to ensure uniform distribution and fedmanually to the volumetric feeder or hopper. From the hopper, the drymix was conveyed with an auger to the pre-conditioner inlet andgravitationally fed into the conditioning cylinder at a rate of 0.80 to1.10 kg/min (1.76-2.42 lb/min). The water was introduced into theconditioning cylinder at the rate of 0.07 to 0.25 kg/min (0.15-0.55lb/min), and steam was injected into the conditioning cylinder at therate of 0.05-0.15 kg/min (0.11-0.33 lb/min). The steam flow into theconditioning cylinder is carefully monitored and maintained at 60° C. to70° C. (140° F.-160 ° F.) to prevent gelatinization of starch an ofstarch hydroxyl groups that will interact with the functional groups ofproteins to form lumps. High temperatures and water are also known toinitiate protein-protein interactions and lumps formation. The lumps areknown to impede the smooth flow characteristics of the dry mix byblocking the feed trough. The conditioning cylinder paddles rotating at680-720 rpm continuously stirred and conveyed the conditioned dry mix tothe outlet, and gravitationally fed into the extruder barrel (inlet).The conditioned dry feed mix was introduced into the extruder barrel ata rate of 0.80 to 1.10 kg/min (1.76-2.42 lb/min) using the extruderscrew speed of from 275-450 rpm. TABLE 15 Soy, Soy/Caseinate andCaseinate Proteins Formulations at 80% and 90% Protein Levels. SampleSample Sample Sample Sample Sample Sample Sample Sample 22 23 24 25 2627 28 29 30 (%) (%) (%) (%) (%) (%) (%) (%) (%) SUPRO ® 8000 75.5 75.575.5 85.0 85.0 — — — — SUPRO ® 248 15.1 — — — — — — — — Ca-Caseinate —15.1 — 14.7 — 90.6 — 99.7 — Na-Caseinate — — 15.1 — 14.7 — 90.6 — 99.7Tapioca Starch 9.1 15.7 15.7 — — 9.1 9.1 — — Soy Lecithin — DicalciumPO₄ 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Salt (NaCl) 0.1 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1

The extruder used in the example was a Wenger TX 52 manufactured byWenger, Inc. (Sabetha, Kans.) with a double barrel twin screw, L/D ratioof 13.5:1 and four heating zones. The screw configuration used in theexample was divided into four section. The first section was conveying;the second section was mixing and shearing; the third section wascompressing; and, the fourth section was shearing and compressing. Wateris introduced into the extruder barrel at a rate of 0.17-0.30 kg/min(0.37-0.66 lb/min) without steam injection. The extruder barreltemperatures in zones 3 and 4 were controlled by water. The temperatureprofile of the Wenger TX 52 is presented in Table 16. TABLE 16 Wenger TX52 Extruder Barrel Temperatures. Pre- Extrusion Extrusion ExtrusionExtrusion Conditioner Zone 1 Zone 2 Zone 3 Zone 4 ° C. ° C. ° C. ° C. °C. 60-70 20-30 40-80  50-105  60-130 (140-158° (68-86° (104-176°(122-221° (140-266° F.) F.) F.) F.) F.)

The dry feed mixes with ≧1.1 ratios (soy protein/caseinate) in thesamples did not utilize steam in the conditioning cylinder. Theprocessing temperatures in the extruder barrel zones, most especiallyzones 3 and 4, were also below 90° C. (194° F.). The high dairy proteindry mixes were sensitive to high temperatures, shear and pressures.These dry mixes also expanded even at low temperatures, shear andpressure.

The conditioned dry feed mix was texturized or cooked in the extruderbarrel with mechanical energy generated from the extruder screw speedand shear at high temperatures to reach the glass transitiontemperature. At high temperatures, shear and pressure, the dry feed mixmelts and interacts with water and other ingredients to form apseudoplastic like material which is extruded through a Y-adapter backupplate having a diameter of 0.125 inches (3.125 mm) before passingthrough the extrusion die with 1.5 mm or 2 mm diameter holes. Also, 1×3nun or 1×4 mm oval die holes were used in the study. The extrudatescoming out of the die holes are cut with a six (6) flexible bladed kniferotating at 1500-3500 rpm to obtain the product size, density andgranulation. A variety of extruded products (nuggets, cereal, expandedsnacks, etc.) were obtained depending on the knife speed.

The extruded products were dried with a single band Proctor dryer(Proctor & Schartz, SCM Corporation, Philadelphia, Pa.) at temperaturesof about 115° C.-136° C. (240° F.-277° F.) and residence time of 13-20min. The dried extruded products were sieved using a US #3 and US #8Sweco sieves to remove the fines.

The texture or hardness of the extruded products was determined using aTexture Analyzer, Model #TA.TXT2 with a 25 kg load cell manufactured byStable Micro Systems Ltd. (England). The density and texture of 70%,75%, 80%, 85% and 90% soy protein nuggets are presented in Table 17.TABLE 17 Density and Texture of High Soy Protein Nuggets. Protein (%)Density (g/cc) Texture (g) 70 0.235 21680.1 75 0.247 23918.7 80 0.25625230.2 85 0.234 22526.4 90 0.257 24201.0

The physical properties (density, texture, color and particle sizedistribution) of extruded 70% soy, soy/caseinate protein products atdifferent protein ratios are presented in Table 18. Whereas, thephysical properties of extruded 80% and 90% soy, soy/caseinate andcaseinate products are presented in Table 19. TABLE 18 PhysicalCharacteristics of 70% Soy and Soy/Caseinate Protein Nuggets atDifferent Protein Ratios. Sample: 13 14 15 16 17 18 19 20 21 70% Prot70% Prot 70% Prot 70% Prot 70% Prot 70% Prot 70% Prot 70% Prot 70%Density (g/cc) 0.236 0.252 0.204 0.155 0.095 0.200 0.244 0.127 0.106Density (lb. cu. ft.) 14.719 15.729 12.74 9.660 5.935 12.447 15.2507.948 6.615 Color L Value 56.67 58.19 58.78 71.25 66.22 56.97 64.0269.36 72.35 A Value 3.11 3.08 2.92 1.17 0.97 2.77 1.26 0.55 −0.53 BValue 18.92 19.64 20.00 17.49 20.12 19.23 17.54 18.00 18.82 Granulation% US#4 0.36 0.00 29.63 25.01 100.04 3.67 0.32 96.41 91.79 US#6 98.6298.5 70.34 74.51 0.13 96.12 98.42 3.74 5.8 US#8 0.67 1.40 0.16 0.06 0.030.38 1.06 0.01 2.22 PAN 0.17 0.41 0.17 0.36 0.14 0.11 0.24 0.2 0.65Texture Analyser FORCE (g) 8931.7 12630.5 7486.6 20564.9 9915.7 5128.3226873.1 27809.7 23794

TABLE 19 Physical Characteristics of 80% and 90% Soy, Soy/Caseinate andCaseinate Protein Nuggets. Sample: 22 23 24 25 26 27 & 28 29 & 30 80%80% 80% 90% 90% 80% 90% Protein Protein Protein Protein Protein ProteinProtein Density (g/cc) 0.122 0.103 0.130 0.110 0.170 0.092 0.097 Density(lb. cu. ft.) 7.582 6.443 8.106 6.878 10.50 5.741 6.053 Color L Value56.71 57.56 58.31 57.48 55.50 70.25 72.35 A Value 2.44 2.80 2.12 2.862.49 0.66 −0.39 B Value 18.09 19.40 18.65 19.80 18.82 19.30 18.32Granulation % US#4 0.14 0.29 0.00 0.03 0.00 100.0 100.0 US#6 96.79 99.6283.77 77.75 1.34 0.03 0.01 US#8 3.26 0.27 15.94 22.10 98.21 0.01 0.00PAN 0.12 0.13 0.63 0.37 0.62 0.01 0.00 Texture Analyser FORCE (g)24678.39 10142.95 31486.86 22914.78 48268.37 7249.24 5465.67

Example 4

This example illustrates the preparation of a soy protein nuggetcomprised of greater than 70% protein using unhydrolyzed soy protein invarious feed mixture formulations with a resultant nugget density ofbetween 0.10 and 0.40 g/cc.

The feed mixtures are described below in Table 20. TABLE 20 FeedComposition 72% Protein Product SUPRO ® 620 79.8% 79.4% Native TapiocaStarch 18.8% 10.0% Rice Flour 10.3% Fibrim 1.1% Salt 0.3% 0.3%

The ingredients of each feed mixture were mixed in an ingredient blenderfor 45 minutes to ensure uniform distribution. The dry feed mixture wasthen dumped into totes to be transported to the feed hopper of aloss-in-weight feeder and fed to the pre-conditioning cylinder at a rateof 59.6 to 60.1 kg/hr (13 1.4-132.5 lb/hr) in which the dry mix waspre-conditioned with water. Water was introduced to the pre-conditionerat a rate of 15.7 kg/hr. The mixture in the pre-conditioner wascontinuously stirred with a paddle rotating at 700 rpm.

The conditioned feed mix was then introduced to the inlet of theextruder barrel inlet by gravity at a rate of 75.3-75.8 kg/hr (166-167lb/hr). The extruder was a twin-screw extruder, Wenger TX-52manufactured by Wenger, Inc (Sabetha, Kans.) having an L/D ratio of13.5:1, 4 cooling zones and a screw speed of 427 to 432 rpm. Thetemperature of each barrel zone is described in Table 21. TABLE 21 Zone1 Zone 2 Zone 3 Zone 4 Die Temp. Temp. Temp. Temp. Temp. Formula (° C.)(° C.) (° C.) (° C.) (° C.) Fibrim Not 55-56 98-99 101-103 101-104Recorded Rice Not 55 97 100-101 101-102 Flour Recorded

The conditioned feed mix was cooked in the extruder barrel withmechanical energy generated from the screw rpm/shear to reach the glasstransition temperature. At high temperatures, shear and pressure thefeed mix melts and interacts with water and other ingredients to form aplastic like material before passing through an extrusion die. Theextrudate was cut using a 6 blade knife at 1994 to 2163 rpm.

The extrudate was pneumatically conveyed to a Proctor Schwartz singlebelt conveyor dryer where the nugget was dried for approximately 16minutes at 250° F. The density and color of the resultant nugget isshown in Table 22. TABLE 22 Density Color Color Color Formulation (g/cc)L A B 72% Protein with Fibrim 0.32 60.8 2.69 20.02 72% Protein with RiceFlour 0.31 62.0 2.56 20.03

Example 5

This example illustrates the preparation of soy protein nuggetscomprising different levels of cocoa powder to deliver flavor and colorin the final nuggets and comprising different levels of soy proteinisolate (hydrolyzed/unhydrolyzed) to yield 75% to 82% protein in finalproduct. TABLE 23 Sample Ingredient -31 -32 -33 34 35 SUPRO ® 8000 ISP89.0% 89.0% 85.0% 85.0% 77.7% SUPRO ® 620 ISP 0.0% 0.0% 0.0% 0.0% 9.0%Cocoa Powder 5.0% 6.5% 8.0% 8.0% 7.0% Native Tapioca 5.7% 4.2% 6.7% 0.0%6.0% Starch Rice flour 0.0% 0.0% 0.0% 6.7% 0.0% Dicalcium phosphate 0.3%0.3% 0.3% 0.3% 0.3%

TABLE 24 sample Ingredient 107 - 02 107 - 03 108 - 01 108 - 02 108 - 03SUPRO ®8000 ISP 87.7% 85.7% 86.0% 86.0% 86.0% SUPRO ®620 ISP 5.0% 5.0%0.0% 0.0% 0.0% Cocoa Powder 7.0% 7.0% 1.0% 3.0% 7.0% Native Tapioca 0.0%0.0% 12.7% 10.7% 6.7% Starch Soy Fiber 0.0% 2.0% 0.0% 0.0% 0.0%Dicalcium phosphate 0.3% 0.3% 0.3% 0.3% 0.3%

As show in Tables 23 and 24, the main ingredient to produce High ProteinNuggets with Cocoa is SUPRO® 8000, (The Solae Company, St. Louis, Mo.)this is a hydrolyzed isolate, similar to SUPRO® 670; Native TapiocaStarch, Rice Flour and Soy Fiber function as developing the expansion inextrusion.

SUPRO® 620, Cocoa Powder (Bloomer Chocolate, (Chicago, Ill.) andDicalcium Phosphate have the ability to modify the cell structure of thefinal product. They reduce the texture cell size resulting in denserfinal products.

The ingredients of each mixture were mixed in a blender for about 20-30minutes to insure uniform distribution. The dry feed was manually fed tothe extruder hopper, and then fed to a preconditioner at 1.8-2.2 LB/Min.Steam was added to the preconditioner to help the ingredients getpre-hydrated prior to extrusion. Steam was added to obtain a temperaturebetween about 38° C. to about 71° C. (100° F. to 160° F.) at thepreconditioner discharge. The steam addition was adjusted to thecylinder to achieve the right final product density; the addition ofsteam helps to obtain improved expansion.

The preconditioned dry mix was introduced to the extruder throughout atransition to minimize waste and dust. The extruder rate was the same asthe rate fed to the preconditioner (1.8-2.2 LB/Min), when stableconditions are maintained. The dry mix residence time in thepreconditioner was about 3-5 minutes.

The extruder used for the production of these products was a three zonesand a head section twin-screw extruder, Wenger Model TX-52 manufacturedby Wenger Manufacturing Inc. (Sabetha, Kans.) with a 13.5/1 L/D ratio.

The screw configuration used in the example was divided into foursections. The first section was conveying; the second section was mixingand shearing; the third section was compressing; and, the fourth sectionwas shearing and compressing.

Water was pumped into the first extruder barrel at 0.40-0.60 Lb/Min. Thebarrel temperatures obtained were generated by the extruder set up,shear and mechanical energy introduced to the system. These products canalso be produced using external heating such as electrical heating,steam injection and hot oil controlled by a Mokon unit.

Extruder temperatures are normally Zone 1 “feeding”38° C.-71° C. (100°F.-160° F.); Zone 2 77° C.-99° C. (170° F.-210° F.); Zone 3 104° C.-121°C. (220° F.-250° F.) and cone head 104° C.-127° C. (220° F.-260° F.).

The dry mix was fed into the extruder and cooked by shear generated byscrew configuration, die design, feed/liquid rate, the nature ofingredients and extruder rpm; normally running about 400-500 rpm toachieve the right product density and texture.

After the dry mix was cooked and extruded, it exited the die (one insert1.5 mm diameter 3 holes); steam was released creating product expansion,the product was face cut by a six (6) blade cutter holder at about2500-3200 rpm to achieve the desired product particle size.

The product was dried in a continuous single pass Proctor Dryer at 121°C. (250° F.) for about 15 to 20 minutes to obtain less than 5.0% productmoisture. Then the product was packaged and analyzed.

The results of this analysis are in Tables 25 & 26: TABLE 25 Sample 3132 33 34 Density g/cc 0.275 0.288 0.245 0.280 Color Hunter L value 21.5720.55 19.59 19.82 A value 1.87 1.68 1.46 1.66 B value 3.62 3.12 2.673.03 Moisture (%) 1.66 3.37 2.10 0.83 Granulation (%) On U.S. #4 0.420.43 0.58 0.17 On U.S. #6 77.03 87.86 93.15 1.00 On U.S. #8 21.31 11.256.11 98.54 Pan 1.24 0.46 0.16 0.29 Texture Analysis Force (g) 4583244742 30132 38484

The amount and type of carbohydrates in formulation affected productdensity as observed in Table 25. Samples 31 and 32 produced densersamples than Sample 33. Sample 34 produced a denser sample than Sample33, due to different starch rice flour in the sample (lack of productexpansion, resulting in smaller particles and high percentage on U.S. #8Screen).

The percentage differences of cocoa powder in these formulas are low andthese minimum levels did not show any differences in product color.TABLE 26 Sample 35 36 37 Density g/cc 0.273 0.330 0.350 Color Hunter Lvalue 18.72 19.25 20.31 A value 1.41 1.67 1.75 B value 2.58 3.04 3.27Moisture (%) 2.44 2.71 3.95 Granulation (%) On U.S. #4 0.00 0.09 0.00 OnU.S. #6 25.46 4.04 1.81 On U.S. #8 73.86 94.94 93.56 Pan 0.68 0.93 4.63Texture Analysis Force (g) 23838 45172 Maximized TA

The elimination of tapioca starch from the samples produced higherdensity samples as seen in Samples 36 and 37 in Table 27. SUPRO® 620 inthe samples produces higher density samples. TABLE 27 Sample 38 39 40Density g/cc 0.243 0.215 0.218 Color Hunter L value 33.61 24.85 16.64 Avalue 1.65 1.71 1.38 B value 8.00 4.54 2.77 Moisture (%) 1.13 1.51 2.28Granulation (%) On U.S. #4 0.10 0.00 0.21 On U.S. #6 87.99 75.24 91.40On U.S. #8 11.45 24.13 8.25 Pan 0.46 0.63 0.14 Texture Analysis Force(g) 14003 12592 12287

The amount of native tapioca starch in all three samples was enough toproduce samples under 0.25 g/cc in density. These samples show directcorrelation between the levels of cocoa powder in formulation to Huntercolor; in particular L and B values. Higher levels of cocoa powder informulation produced darker samples (lower L values).

The texture force values were measured by a Texture Analyzer, Model #TA.TXT2 with 25 Kg load cell manufactured by Stable Micro Systems Ltd.(England).

Product density was directly related to the amount of protein and starchin the sample.

Higher percent protein in the sample yields a denser product; lowerpercent starch yields a denser product.

Processing conditions can be adjusted to change product density byreducing or increasing extruder rpm and/or water input to the process;these variables affected product density and texture. TABLE 28 See datain the Table 27: Sample 38 38A 39 39A 40 40A Density g/cc 0.243 0.1920.215 0.247 0.218 0.175 TA: Force Values (g) 14003 12165 12592 1958612287 13054 Ext. Screw Speed rpm 360 500 450 400 380 450 Water rateLb/Min 0.44 0.44 0.46 0.48 0.53 0.42

The rest of the processing conditions were maintained constant (Feedrate 55 Kg/Hr, steam input same valve opening “Preconditionertemperature 8° C.-11° C.(47° F.-52° F.)”, cutter speed 3300 rpm, dryertemperature, extruder barrel temperatures, etc.).

Preferred formulations are provided in the following formulationexamples. All percents (%) are by weight.

Nutritional Bar (Sheet and Cut Type) Ingredients % Marshmallow mixture39.0 sugar polydextrose corn syrup margarine water corn syrup High soyprotein nuggets 31.5 Dried Apples 13.5 Dried cranberries 13.0 Soybeanoil 2.0 Cranberry juice concentrate 1.0 Total 100

Acidic pH Beverage Ingredients % Water 84.59 Sucrose 4.29 Ground,Comminuted high soy protein nuggets 1.65 Fructose 2.91 Carrotconcentrate, 42 Brix 4.02 Citric acid 0.10 Pectin 0.45 Vitamin Premix1.09 Phosphoric acid (75%) 0.7 Natural and Artificial Flavor 0.2 Total100.00

Ground Meat, Beef Patties Ingredient % Beef Trim (10% Fat) 59.00 BeefTrim (15% Fat) 10.00 Beef Trim (50% Fat) 25.00 Water 5.0 Ground,Comminuted high soy protein nuggets 1.0 Total 100.00

Smoked Italian Sausage Ingredients % Pork trimmings 49.20 Chicken(Mechanically deboned) 15.00 Pork fat trimmings 10.00 Water 20.00 Salt1.70 Curing salt (6.25% NaNO₂) 0.20 Phosphate 0.30 Sodium ascorbate 0.05Ground textured soy protein product 1.60 Non fat dry milk 0.80 Smokeflavor 0.25 Paprika powder 0.25 Fennel 0.25 Red pepper 0.15 White pepper0.15 Anise 0.10 Total 100.00

Smoked Sausage Ingredients % Pork picnics 48.00 Beef meat 20.00 Turkey(Mechanically deboned) 10.00 Water 15.00 Salt 1.80 Curing salt 0.20Sodium ascorbate 0.05 Corn syrup solids 1.50 Ground textured soy proteinproduct 1.50 Non fat dry milk 1.50 White pepper 0.25 Marjoram 0.10Nutmeg 0.10 Total 100.00

Beef Smoked Sausage Ingredients % Beef meat 20.00 Beef navels 52.00Water 20.00 Salt 2.10 Curing salt (6.25% NaNO₂) 0.15 Sodium ascorbate0.05 Corn syrup 2.20 Ground textured Soy protein product 2.20 Non fatdry milk powder 0.60 Onion powder 0.20 Seasoning 0.50 Total 100.00

Variety Meat Smoked Sausage Ingredients % Beef tripe (flaked/ground)16.00 Beef head meat (flaked/ground) 10.00 Beef meat (pre-cured) 10.00Beef heart emulsion 10.00 Beef tongue 16.00 Pork meat (pre-cured) 10.00Chicken (Mechanically deboned) 10.00 Water 10.00 Salt 2.30 Curing salt(6.25% NaNO₂) 0.15 Sodium ascorbate² 0.05 Corn syrup 2.30 Groundtextured Soy protein product 2.30 Seasoning 0.90 Total 100.00

The present invention is not limited to the above embodiments and can bevariously modified. The above description of preferred embodiments isintended only to acquaint others skilled in the art with the invention,its principles and its practical application so that others skilled inthe art may adapt and apply the invention in its numerous forms, as maybe best suited to the requirements of a particular use.

With reference to the use of the word(s) “comprise” or “comprises” or“comprising” in this entire specification (including the claims below),it is noted that unless the context requires otherwise, those words areused on the basis and clear understanding that they are to beinterpreted inclusively, rather than exclusively, and that it isintended each of those words to be so interpreted in construing thisentire specification.

1. A protein extrudate comprising at least about 70% by weight proteinon a moisture-free basis having a color L value of greater than 50 and adensity of from about 0.10 g/cm³ to about 0.40 g/cm³.
 2. The proteinextrudate of claim 1, wherein the 70% by weight protein is comprised ofprotein selected from the group consisting of soy protein, dairy proteinand mixtures thereof.
 3. The protein extrudate of claim 2, wherein thesoy protein is selected from the group consisting of soy proteinisolate, soy protein concentrate and mixtures thereof.
 4. The proteinextrudate of claim 2, wherein the dairy protein is selected from thegroup consisting of calcium caseinate, sodium caseinate, whey proteinisolate, whey protein concentrate and mixtures thereof.
 5. The proteinextrudate of claim 2 comprising from about 2 to about 8 parts by weighthydrolyzed protein per part by weight unhydrolyzed protein.
 6. Theprotein extrudate of claim 5, wherein said hydrolyzed protein exhibits adegree of hydrolysis of less than about 15%.
 7. The protein extrudate ofclaim 1 comprising at least about 80% by weight protein on amoisture-free basis.
 8. The protein extrudate of claim 7, wherein the80% by weight protein is dairy protein.
 9. The protein extrudate ofclaim 1 wherein said protein extrudate is further characterized byhaving a non-fibrous eating texture.
 10. The protein extrudate of claim2, wherein said extrudate is in the form of a powder having an averageparticle size of less than about 10 microns.
 11. The protein extrudateof claim 7, wherein said extrudate is in the form of a powder having anaverage particle size of less than about 10 microns.
 12. The proteinextrudate of claim 1 wherein said extrudate comprises from about 0.001%to about 5% fiber on a moisture free basis.
 13. The protein extrudate ofclaim 7 wherein said extrudate comprises from about 0.001% to about 5%fiber on a moisture free basis.
 14. A functional food ingredientcomprising from about 40% to about 95% by weight meat material and up toabout 4% by weight of a protein product on a total weight basis, theprotein product comprising at least about 70% by weight protein on amoisture-free basis, having a color L value of greater than 50 and adensity of from about 0.10 g/cm³ to about 0.40 g/cm³.
 15. The functionalfood ingredient of claim 14, wherein the 70% by weight protein iscomprised of protein selected from the group consisting of soy protein,dairy protein and mixtures thereof.
 16. The functional food ingredientof claim 15, wherein the soy protein is selected from the groupconsisting of soy protein isolate, soy protein concentrate and mixturesthereof.
 17. The functional food ingredient of claim 15, wherein thedairy protein is selected from the group consisting of calciumcaseinate, sodium caseinate, whey protein isolate, whey proteinconcentrate and mixtures thereof.
 18. The functional food ingredient ofclaim 14 comprising at least about 80% by weight protein on 5 amoisture-free basis.
 19. The functional food ingredient of claim 18,wherein the 80% by weight protein is a dairy protein.
 20. A low densitysnack food product including a majority solids component and a watercomponent with the majority solids component including at least protein,said food product comprising: protein in the range of between about 25%and about 95% by weight of majority solids component and water; water inthe range of between about 1% and about 7% by weight of solids andwater; and said product being characterized by having a crisp texture, acolor L value of greater than 50, and a density in the range of betweenabout 0.02 g/cm³ and about 0.5 g/cm³ based on the weight of solidscomponent and water.
 21. The food product of claim 20, wherein the 70%by weight protein is comprised of protein selected from the groupconsisting of soy protein, dairy protein and mixtures thereof.
 22. Thefood product of claim 21, wherein the soy protein is selected from thegroup consisting of soy protein isolate, soy protein concentrate andmixtures thereof.
 23. The food product of claim 21, wherein the dairyprotein is selected from the group consisting of calcium caseinate,sodium caseinate, whey protein isolate, whey protein concentrate andmixtures thereof.
 24. The food product of claim 20 comprising at leastabout 80% by weight protein on a moisture-free basis.
 25. The foodproduct of claim 24, wherein the 80% by weight protein is dairy protein.26. The food product of claim 20 wherein said product is furthercharacterized by having a non-fibrous eating texture.
 27. The foodproduct of claim 20 wherein the majority solids component includesfiller present in a ratio of filler to protein in the range of betweenabout 5:95 and about 75:25.
 28. The food product of claim 21 wherein theprotein includes at least partially hydrolyzed protein and unhydrolyzedprotein.
 29. The food product of claim 25 wherein the protein includesat least partially hydrolyzed protein and unhydrolyzed protein.
 30. Thefood product of claim 28 wherein the at least partially hydrolyzedprotein includes at least partially hydrolyzed protein isolates and theunhydrolyzed protein includes at least one of protein isolates andprotein concentrates wherein the at least partially hydrolyzed proteinis present in the ratio of between about 80:20 and about 55:45 to theunhydrolyzed protein.
 31. The food product of claim 29 wherein the atleast partially hydrolyzed protein includes at least partiallyhydrolyzed protein isolates and the unhydrolyzed protein includes atleast one of protein isolates and protein concentrates wherein the atleast partially hydrolyzed protein is present in the ratio of betweenabout 80:20 and about 55:45 to the unhydrolyzed protein.
 32. The foodproduct of claim 30, wherein the 70% by weight protein is comprised ofprotein selected from the group consisting of soy protein, dairy proteinand mixtures thereof.
 33. The food product of claim 21, wherein the soyprotein is selected from the group consisting of soy protein isolate,soy protein concentrate and mixtures thereof
 34. The food product ofclaim 21, wherein the dairy protein is selected from the groupconsisting of calcium caseinate, sodium caseinate, whey protein isolate,whey protein concentrate and mixtures thereof.
 35. The food product ofclaim 30 comprising at least about 80% by weight protein on amoisture-free basis.
 36. The food product of claim 35, wherein the 80%by weight protein is dairy protein.
 37. A low density, low moisturecontent proteinaceous food product comprising a principal solidcomponent and containing between about 1% and about 7% water, saidprincipal solid component comprising protein in a concentration betweenabout 25% and about 95% by weight of the sum of the water content ofsaid product and the dry basis weight of said principal solid component,said product being characterized by a crisp texture, a color L valuegreater than 50 and a density in the range of between about 0.02 g/cm³and about 0.5 g/cm³ based on the weight of said principal solidcomponent and water.
 38. The food product of claim 37 wherein saidprincipal solid component further comprises a filler in a weight ratioto protein between about 5:95 and about 75:25.
 39. The food product ofclaim 37, wherein the 70% by weight protein is comprised of proteinselected from the group consisting of soy protein, dairy protein andmixtures thereof.
 40. The food product of claim 39, wherein the soyprotein is selected from the group consisting of soy protein isolate,soy protein concentrate and mixtures thereof.
 41. The food product ofclaim 39, wherein the dairy protein is selected from the groupconsisting of calcium caseinate, sodium caseinate, whey protein isolate,whey protein concentrate and mixtures thereof
 42. The food product ofclaim 37 comprising at least about 80% by weight protein on amoisture-free basis.
 43. The food product of claim 42, wherein the 80%by weight protein is dairy protein.
 44. The food product of claim 39wherein the protein includes at least partially hydrolyzed protein andunhydrolyzed protein.
 45. The food product of claim 43 wherein theprotein includes at least partially hydrolyzed protein and unhydrolyzedprotein.
 46. A low density, low moisture content proteinaceous foodproduct comprising a proteinaceous solid matrix and containing betweenabout 1% and about 7% water, said matrix comprising protein in aconcentration between about 25% and about 95% by weight of the sum ofthe water content of said product and the dry basis weight of saidmatrix, said product being characterized by a crisp texture, a color Lvalue of greater than 50 and a density in the range between about 0.02g/cm³ and about 0.5 g/cm³.
 47. The food product of claim 46 wherein saidmatrix further comprises a filler in a weight ratio to protein betweenabout 5:95 and about 75:25.
 48. The food product of claim 46, whereinthe 70% by weight protein is comprised of protein selected from thegroup consisting of soy protein, dairy protein and mixtures thereof. 49.The food product of claim 48, wherein the soy protein is selected fromthe group consisting of soy protein isolate, soy protein concentrate andmixtures thereof.
 50. The food product of claim 48, wherein the dairyprotein is selected from the group consisting of calcium caseinate,sodium caseinate, whey protein isolate, whey protein concentrate andmixtures thereof.
 51. The food product of claim 46 comprising at leastabout 80% by weight protein on a moisture-free basis.
 52. The foodproduct of claim 51, wherein the 80% by weight protein is dairy protein.53. The food product of claim 46 wherein the protein includes at leastpartially hydrolyzed protein and unhydrolyzed protein.
 54. The foodproduct of claim 52 wherein the protein includes at least partiallyhydrolyzed protein and unhydrolyzed protein.
 55. A low density, lowmoisture content proteinaceous food product comprising a proteinaceoussolid extrudate and containing between about 1% and about 7% water, saidextrudate comprising protein in a concentration between about 25% andabout 95% by weight of the sum of the water content of said product andthe dry basis weight of said extrudate, said product being characterizedby a crisp texture, a color L value greater than 50, and a density inthe range between about 0.02 g/cm³ and about 0.5 g/cm³.
 56. The foodproduct of 55 wherein said extrudate further comprises a filler in aweight ratio to protein between about 5:95 and about 75:25.
 57. The foodproduct of claim 55, wherein the 70% by weight protein is comprised ofprotein selected from the group consisting of soy protein, dairy proteinand mixtures thereof.
 58. The food product of claim 57, wherein the soyprotein is selected from the group consisting of soy protein isolate,soy protein concentrate and mixtures thereof.
 59. The food product ofclaim 57, wherein the dairy protein is selected from the groupconsisting of calcium caseinate, sodium caseinate, whey protein isolate,whey protein concentrate and mixtures thereof.
 60. The food product ofclaim 55 comprising at least about 80% by weight protein on amoisture-free basis.
 61. The food product of claim 60, wherein the 80%by weight protein is dairy protein.
 62. The food product of claim 57wherein the protein includes at least partially hydrolyzed protein andunhydrolyzed protein.
 63. The food product of claim 61 wherein theprotein includes at least partially hydrolyzed protein and unhydrolyzedprotein.
 64. A low density, low moisture content proteinaceous foodproduct comprising between about 1% and about 7% water and between about25% and about 95% by weight of protein, wet basis, said product beingcharacterized by a crisp texture, a color L value greater than 50, and adensity in the range between about 0.02 g/cm³ and about 0.5 g/cm³. 65.The food product of claim 64, wherein the 70% by weight protein iscomprised of protein selected from the group consisting of soy protein,dairy protein and mixtures thereof.
 66. The food product of claim 65,wherein the soy protein is selected from the group consisting of soyprotein isolate, soy protein concentrate and mixtures thereof.
 67. Thefood product of claim 65, wherein the dairy protein is selected from thegroup consisting of calcium caseinate, sodium caseinate, whey proteinisolate, whey protein concentrate and mixtures thereof.
 68. The foodproduct of claim 64 comprising at least about 80% by weight protein on amoisture-free basis.
 69. The food product of claim 68, wherein the 80%by weight protein is dairy protein.